LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 


Class 


CELLULOSE,  CELLULOSE  PRODUCTS, 
AND  RUBBER  SUBSTITUTES. 


CELLULOSE,  CELLULOSE  PRODUCTS, 
AND  ARTIFICIAL  RUBBER, 

COMPRISING 

THE  PREPARATION  OF  CELLULOSE  FROM  WOOD  AND  STRAW  ;  MANUFACTURE  OF 

PARCHMENT  ;  METHODS  OF  OBTAINING  SUGAR  AND  ALCOHOL,  AND  OXALIC 

ACID  ;    PRODUCTION    OF  VISCOSE   AND   VISCOID,    NITRO-CELLULOSES, 

AND  CELLULOSE   ESTERS,    ARTIFICIAL  SILK,    CELLULOID, 

RUBBER  SUBSTITUTES,  OIL-RUBBER,  AND  FACTIS. 


BY 

DR.  JOSEPH  BERSCH. 


AUTHORIZED  TRANSLATION  FROM  THE  GERMAN, 

BY 

WILLIAM  T.  BRANNT, 

EDITOR  OP  "THE  TECHNO-CHEMICAL  RECEIPT  BOOK." 


OF  THE. 

UNIVERtiT 

OF 

^ALIFOR*^ 


JTRA-TED      BV     F-ORTY-OME     ENORAVINO8. 


PHILADELPHIA : 

HENRY  CAREY  BAIRD  <fe  CO., 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS,  AND  IMPORTERS, 

810  WALNUT  STREET. 

LONDON : 
KEG  AN  PAUL,  TRENCH,  TRUBNER  &  CO.,  LTD., 

DBYDEN   HOUSE,  43,  GERHARD   STREET,  SOHO. 

1904 


COPYBIGHT,    BY 

HENRY  CAREY  BAIRD  &  CO., 
1904. 


PRINTED  BY  THE 

WICKERSHAM  PRINTING  CO., 

53  and  55  North  Queen  St., 

LANCASTER,  PA.,  U.  S.  A, 


PREFACE. 


AMONG  the  raw  materials  which  nature  has  placed  at  our  dis- 
posal for  industrial  purposes,  Cellulose  has  from  time  immem- 
orial occupied  a  prominent  position,  having  from  prehistoric 
days,  continuously  served  for  the  production  of  tissues,  and  been, 
even  for  thousands  of  years,  employed  as  a  basis  for  the  execu- 
tion of  writings.  By  the  development  of  .the  science  of  chem- 
istry, we  have  become  acquainted  with  a  large  number  of  com- 
pounds, which  have  to  be  considered  as  derivatives  of  Cellulose, 
and  we  have  learned  of  processes  for  the  separation  of  this 
important  body,  in  a  pure  form,  from  wood  and  straw. 

The  nitro-compounds,  which  can  be  prepared  from  Cellulose, 
form  the  starting  point  for  all  the  explosive  bodies  in  use  at  the 
present  time;  and  the  nitro-celluloses  themselves  have  led  to  the 
invention  of  processes  for  the  production  of  so-called  artificial 
silk  and  of  celluloid.  The  discovery  of  the  peculiar  compound, 
to  which  the  term  viscose  has  been  applied,  was  the  initiatory 
step  towards  the  preparation  of  a  series  of  bodies  of  technical 
importance — solutions  of  cellulose  having  created  the  basis  for 
the  preparation  of  lustra-cellulose,  etc.  The  branches  of  in- 
dustry thereby  called  into  existence  have  in  a  comparatively 
short  time  developed  into  noteworthy  manufactures,  and  scarcely 
a  month  passes  by,  without  our  becoming  acquainted  with  new 
applications  of  the  compounds  derived  from  Cellulose. 

It  would  appear  that  the  problem  of  the  production  of  fer- 
mentable sugar,  and  thence  of  that  of  alcohol,  ether,  acetic  acid, 
etc.,  from  Cellulose  or  wood,  has  at  present  more  closely  ap- 
proached its  final  solution  than  it  had,  even  a  few  years  since; 
and  by  the  perfection  of  methods  for  this  purpose  a  radical  revo- 
lution in  certain  industries  may  eventually  be  looked  for. 

In  consideration  of  the  far-reaching  importance  to  the  indus- 
tries of  Cellulose  and  the  products  capable  of  being  prepared 

(v) 


VI  PREFACE. 

from  the  latter,  the  author  has  endeavored  to  bring  together  in 
a  comprehensive  manner  everything  that  has  up  to  the  present 
time  become  known  on  this  subject,  and  it  is  hoped,  that  he  has 
produced  a  work  which  gives  clear  explanations  of  all  questions 
pertaining  to  Cellulose  and  the  products  obtainable  from  it,  and 
which  will  serve  as  a  hand-book  for  all  who  may  be  profession- 
ally interested — from  the  forester  to  the  manufacturer  of  arti- 
ficial silk,  lustra-cellulose  and  celluloid. 

By  reason  of  their  extensive  use  for  insulating  purposes  for 
electric  lines,  etc. ,  substances  which  are  available  as  substitutes 
for  rubber  have  acquired  great  industrial  importance,  and  a 
comprehensive  description  of  their  preparation  is  also  here  given, 
and  it  is  believed  may  serve  to  arouse  the  interest  of  a  large 
body  of  manufacturers. 

DR.  J.  BERSCH. 


CONTENTS. 


i. 

CELLULOSE. 

PAGE 

Distribution  of  cellulose  throughout  nature;  Structure  of  plants;  Change 
of  cellulose  vessels  into  wood  vessels 1 

Occurrence  of  cellulose;  Occurrence  of  cellulose  in  the  animal  and  veg- 
etable kingdoms;  Cellulose  formerly  at  our  disposal;  Straw  as  a  mater- 
ial for  cellulose;  Deficiencies  of  pulp  and  paper  from  straw  ...  2 

Employment  of  wood  for  the  preparation  of  cellulose,  a  modern  achieve- 
ment; Chemical  nature  of  wood;  Encrusting  substance  of  wood;  Cotton.  3 

Fruit  of  the  cotton  plant,  described  and  illustrated;  Appearance  of  the 
cotton  fibre  ............  4 

Cotton  fibres,  described  and  illustrated;  Determination  of  the  value  of  a 
Variety  of  cotton;  Short-staple  and  long-staple  cotton  ....  5 

Chemical  composition  of  cotton;  Other  fibre-producing  plants  and  natural 
sources  of  cellulose-fibres;  Preparation  of  chemically  pure  cellulose 
from  cotton;  Properties  of  cellulose;  Formula  of  cellulose  ...  6 

Percentage  composition  of  cellulose;  Transformation  of  substances  in  the 
living  plant-organism;  Conversion  of  cellulose  into  soluble  substances; 
Digestibility  of  cellulose  by  carnivorous  animals  and  human  beings  .  7 

Solubility  of  cellulose;  Solvents  for  cellulose;  Behavior  of  cellulose  to- 
wards acids;  Effect  of  water  upon  cellulose 8 

Hydrocellulose  and  its  composition;  Mode  of  manufacture  on  a  large 
scale  of  hydrocellulose 9 

R.  Sthamer's  process  for  the  preparation  of  larger  quantities  of  hydro- 
cellulose  »  ..........  10 

Preparation  of  hydrocellulose  with  the  use  of  hydrochloric  acid;  Behavior 
of  cellulose  towards  acids  .  .  .  .  .  .  .  .  .11 

Upon  what  the  various  processes  for  the  preparation  of  alcohol  from  cel- 
lulose or  wood  are  based;  Action  of  sulphuric  acid  upon  cellulose; 
Formation  of  amyloid  .  .  ,  "  .  .  .  .  .  .12 

Action  of  hydrochloric  acid  and  of  sulphurous  acid;  Action  of  organic 
acids;  Chemical  changes  effected  by  nitric  acid;  Effect  of  the  acid 
sulphites  of  the  alkalies  and  alkaline  earths  ...  .  .  .13 

Combinations  formed  by  cellulose  with  organic  acids;  Behavior  of  cellu- 
lose towards  alkalies;  Action  of  caustic  alkalies;  Mercerization  and  its 
invention  by  John  Mercer;  Conversion  of  cellulose  into  oxalic  acid  .  14 

(vii) 


Vlll  CONTENTS. 

PAGB 

Behavior  of  cellulose  at  an  increased  temperature;  Destructive  distillation 
of  cellulose  and  products  formed  thereby;  Cellulose  the  basis-material 
of  a  large  series  of  combinations  of  great  technical  importance  .  .  15 

Industrial  uses  of  cellulose;  Vegetable  parchment;  Cellulose  sulphocar- 
bonate  or  viscose;  Nitro-celluloses  .  .  .  .  .  .16 

Artificial  silk;  Celluloid;  Conversion  of  cellulose  into  fermentable  sugar; 
Production  of  cellulose;  Former  sources  of  cellulose  .  17 

Plants  utilized  for  the  production  of  cellulose;  Constitution  of  paper; 
First  experiments  for  the  purpose  of  obtaining  cellulose  from  straw  .  18 

Experiments  for  the  purpose  of  obtaining  cellulose  from  wood,  and  final 
success  in  this  respect  .  .  .  .  ....  .  .19 

Invention  of  a  processs  for  the  solution  and  destruction  of  the  lignin  or 
encrusting  substance  of  wood;  Substances  used  for  this  purpose;  Ex- 
periments for  the  production  of  textile  threads  from  cellulose;  Phases 
of  the  historical  development  of  the  production  of  cellulose  from  wood.  20 

Possibility  of  obtaining  cellulose  from  wood  in  the  form  of  textile  fibres.     21 

II. 

WOOD-STUFF  OR  MECHANICAL  WOOD-PULP. 

Definition  of  the  term  wood-stuff  or  mechanical  wood-pulp;  Chief  use  of 
wood-stuff;  Origin  of  the  fundamental  idea  of  the   process  of  wood 
grinding;    First  patents  granted  for  the  process     ...      .         ...     22 

Execution  of  Voelter's  process  of  wood  grinding;  Wood  for  grinding; 
Most  suitable  varieties  of  wood     .         .         .         .         ...         .23 

Preparation  of  the  wood  to  be  ground;  Machine  for  cutting  away  the 
bark,  described  and  illustrated      ........     24 

Machines  for  the  removal  of  the  knots,  described  and  illustrated       .         .     25 
Spliting  machine,  described  and  illustrated       ......     26 

Wood-grinding  machines;  Essential  parts  of  every  kind  of  machine  for 

grinding  wood 27 

Voelter's  grinding  machine,  described  and  illustrated       .         .         .         .28 

A.  Oser's  grinding  machine,  described  and  illustrated       .         .         .         .30 

Freitag's  grinding  machine,  described  and  illustrated       .         .         .         .31 

Abadie's  grinding  machine,  described  and  illustrated        .         .         .         .32 

Liebrecht'  s  grinding  machine  .........     33 

Use  of  hydraulic  pressure  for  pressing  the  wood  against  the  grindstone; 

Water  used  for  grinding;  Filtration  of  the  water  used  for  grinding       .     34 
Sorting  the  ground   mass;  Sorters  for  sorting   the   wood-stuff;  Voith's 

shaking  sieves,  described  and  illustrated 35 

Mode  of  operation  of  the  shaking  sieve;  Use  of  cylinder  sieves          .         .     36 

The  refiner,  described  and  illustrated 37 

Use  of  corrugated  rolls  for  the  reduction  of  particles  of  wood    .         .         .38 

Recovery  of  the  finest  particles  of  pulp 39 

Dehydration  of  the  pulp;  The  board -machine;  Mode  of  obtaining  thor- 
oughly dried  pulp 40 


CONTENTS.  IX 

PAGE 

Pulp  for  transporting  long  distances;  Drying  apparatus;  Arrangement  of 
the  apparatus  for  drying  pulp 41 

Properties  of  wood-pulp;  01.  Winkler's  experiments;  Change  of  color  of 
pulp 42 

Bleaching  agents  for  pulp;  Bleaching  by  means  of  sulphurous  acid;  Pulp 
from  steamed  wood;  Quantities  of  substances  which  pass  into  solution  by 
steaming  different  kinds  of  wood  ........  43 

Combinations  formed  in  steaming  wood;  Apparatus  for  steaming  wood; 
Production  of  pulp  from  steamed  wood  ......  44 

Microscopical  examination  of  steamed  wood;  Preparation  of  mechanical 
wood-pulp  by  the  crushing  process;  Chopping  machines,  described  and 
illustrated 45 

Reduction  of  the  small  pieces  of  wood  in  a  stamping  mill;  Usual  mode  of 
working  the  mass  obtained  from  steamed  wood 47 

Difference  between  ground  wood  and  the  original  material        .         .         .48 

III. 

PREPARATION  OF  CELLULOSE  FROM  WOOD.     (  WOOD-CELLULOSE,  CELLULOSE 
IN  THE  TECHNICAL  SENSE  OF  THE  WORD,  CHEMICAL  WOOD-PULP.  ) 

Constitution  of  paper;  Principal  point  in  the  preparation  of  cellulose  from 
wood 50 

Principal  processes  employed  for  the  preparation  of  wood-cellulose; 
Bachet  and  Machard's  method  ........  51 

Preparation  of  cellulose  by  means  of  soda;  First  step  in  the  manufacture; 
Disintegration  of  the  encrusting  substance  .  .  .  .  .  .52 

Substitution  of  sodium  sulphite  for  a  portion  of  the  caustic  soda;  Boiling 
the  chips  of  wood  .  .  .  .  ,  .  .  .  .  .53 

Sinclair's  boiler,  described  and  illustrated 54 

lingerer's  boiling  process          .........     55 

Keegan's  process      ............     56 

Use  of  a  battery  for  lixiviation;  Contrivances  for  washing  cellulose.         .     57 

Preparation  of  cellulose  by  means  of  sodium  sulphite;  Further  working 
of  the  washed  cellulose  .  .  .  ....  .  .58 

Consumption  of  wood  and  chemicals;  Yield  of  finished  cellulose  from 
various  kinds  of  wood;  Preparation  of  cellulose  with  the  assistance  of 
sulphites  (sulphite-cellulose  according  to  Mitscherlich's  process);  Im- 
portance of  an  abundance  of  water;  Quantity  of  water  required  .  .  59 

Preparation  of  the  wood;  Freeing  the  trunks  from  bark;  Reduction  of  the 
wood;  Woods  most  suitable  for  the  preparation  of  sulphite  cellulose  .  60 

Operations  into  which  the  preparation  of  cellulose  by  the  sulphite  process 
may  be  divided;  Preparation  of  the  sulphite  solution  according  to 
Mitscherlich's  process 61 

Limestone  for  the  preparation  of  the  lye;  Preparation  of  the  sulphurous 
acid;  Tests  as  to  whether  combustion  of  the  sulphur  is  complete  .  .  62 

The  absorbing  tower  and  its  arrangement,  described  and  illustrated  .         .     63 


X  CONTENTS. 

PAGE 

Arrangement  of  a  plant    ..*...         .         .         .         .         .65 

Lye  reservoirs;    Causes  of   irregularities   in   the   operation,   and  their 

remedies       .         .         .         .        .        .        .      -  .        .         .         .         .66 

Boiling  the  wood  with  the  lye;  Boiler  for  this  purpose,  described  and 

illustrated;  Brick  work  for  lining  the  boiler,  described  and  illustrated.  67 
Mode  of  heating  the  mass  in  the  boiler;  Proportion  between  wood  and 

lye  .  ' 68 

Test  for  ascertaining  how  much  effective  calcium  bisulphite  is  still  present.  69 
Recovery  of  sulphurous  acid;  Washing  the  cellulose.  .  '  .  .  .70 
Freeing  the  cellulose  from  admixtures;  Arrangement  of  a  stamping  mill 

for  this  purpose  .  *'  ...  ,  •  •  *  •  •  .71 
Defects  of  cellulose  and  their  remedies;  Cause  of  yellowish  or  brownish 

color;  Occurrence  of  white  pieces  not  converted  into  fibre;  Occurrence 

of  black  particles  and  of  larger  brown  bundles  of  fibre  .  .  .  .72 
Change  in  color  of  the  cellulose  during  washing;  Preparation  of  cellulose 

with  the  assistance  of  the  electric  current — Kellner's  process  .  .  73 
Apparatus  used  for  this  purpose,  described  and  illustrated  .  .  .74 
Advantages  of  the  electrical  process;  Preparation  of  cellulose  from  straw; 

Preparatory  operations.  .  .  ,,  .  V  .  .  .  .  .75 

Cutting  and  winnowing  the  straw;  Further  working  of  the  winnowed 

straw;  Boilers  for  working  the  straw  .  '  .  .  '.  .  .  .76 
Bleaching  the  cellulose;  Yield  of  cellulose;  Various  plants  which  are 

utilized  for  the  preparation  of  cellulose  .  .  .  ;  i  •  .77 
Utilization  of  jute  bagging;  Mode  of  working  jute;  Utilization  of  exhausted 

lyes  and  their  neutralization  .  .  .  .  .  ;.  .  .  78 
Recovery  of  soda;  Discharge  of  lyes  into  running  water  when  working 

with  the  sulphite  process;  Dilution  of  the  lyes  .  .~  .  ..  .  79 
Neutralization  of  the  lyes;  A.  Frank's  process;  Utilization  of  sulphite  lyes 

in  tanning     .         .         .         .„       .         .         .         .         .         .         .         .     80 

IV. 

VEGETABLE  PARCHMENT. 

Change  in  unsized  paper  when  subjected  to  the  action  of  sulphuric  acid; 
Chemical  composition  of  vegetable  parchment;  Explanation  of  the 
parchmentizing  action  of  sulphuric  acid  .  .  .  .  .82 

Nature  of  the  paper  to  be  parchmentized;  Paper  suitable  for  parchmentiz- 
ing; Preparation  of  parchment  of  greater  thickness  .  .  .  .83 

Sulphuric  acid  used  for  parchmentizing;  Use  of  so-called  chamber  acid     .     84 

Time  required  for  parchmentizing;  Parchmentizing  apparatus  .         .         .85 

Removal  of  the  last  traces  of  acid  adhering  to  the  paper;  Drying  the  fin- 
ished parchment;  Recovery  of  the  sulphuric  acid  .  .  .  .86 

Properties  of  parchment;  Table  showing  the  changes  paper  undergoes  by 
parchmentizing  ...........  87 

Preparation  of  parchment  of  special  thickness;  Rendering  parchment 
paper  flexible 88 


CONTENTS.  XI 

PAGE 

Coloring  parchment  paper;  Preparation  of  chrome  gl«e  for  joining  to- 
gether parchment  paper  .........  89 

Applications  of  vegetable  parchment;  Vulcanized  cellulose  (vulcanized 
fibre) ,  and  its  preparation;  Process  according  to  the  patent  specification.  90 

Forms  in  which  vulcanized  fibre  is  found  in  commerce    .        .         .         .91 

V. 

PRODUCTION  OF  SUGAR  AND  ALCOHOL  FROM  WOOD-CELLULOSE. 

First  experiments  for  the  conversion  of  cellulose  into  sugar      .         .         .93 

Older  methods;  Zetterlund's  process 94 

Bachet  and  Machard's  process          ........     95 

Other  methods  for  the  production  of  alcohol  from  wood;  Failure  of  an  ex- 
periment for  the  production  of  alcohol  from  beech;  Nature  of  the  wood 

to  be  worked 96 

Varieties  of  wood  suitable  for  the  production  of  alcohol;  Apparatus  to  be 
used  and  mode  of  procedure  in  general          ......     97 

More  modern  methods  for  the  production  of  alcohol  from  wood;  Cutting 
up  the  wood;  Conversion  of  the  cellulose  into  sugar;  Boiling  under 

pressure 98 

Apparatus  used  for  boiling;  Tests  as  regards  the  time  required  for  obtain- 
ing the  largest  possible  quantity  of  sugar       ......     99 

Removal  of  the  hydrochloric  acid;  Neutralization  of  the  sugar  solution  .  100 
Fermentation  of  the  sugar  solution;  Distillation  of  the  fermented  fluid  .  101 
Value  of  alcohol  obtained  from  wood;  Classen's  process  for  the  production 

of  directly  fermentable  sugar  from  wood    ......  102 

A  noteworthy  process  also  patented  by  Classen 1 04 

Main  point  of  the  process         .        ...         .         •        •         •         •         •  105 
Disintegration  of  the  wood  by  means  of  chlorine  or  hypochlorides;  An- 
other process  patented  by  Classen 106 

Modification  of  Classen's  process       .         .        .         .         .         .         .         .  107 

VI. 

PREPARATION  OF  OXALIC  ACID  FROM  WOOD-CELLULOSE. 

Materials  from  which  the  largest  yields  of  oxalic  acid  are  obtained;  Suita- 
bility of  wood  for  the  preparation  of  oxalic  acid  .  »"  •  .  •  .  •  108 

Mode  of  formation  of  oxalic  acid;  Thorn's  investigations;  Yield  of  oxalic 
acid  from  sawdust  .. ".  .  .  -  .  .  .  .  .»  .  .  109 

Table  showing  yield  of  oxalic  acid  under  different  conditions;  Changes 
taking  place  in  sawdust  by  treating  it  with  mixtures  of  caustic  alkalies.  110 

Best  proportions  between  caustic  soda  and  caustic  potash;  Advantage  of 
heating  the  mixture  of  sawdust  and  caustic  alkalies  in  a  thin  layer  .  Ill 

Prevention  of  the  turbulent  reaction  during  fusion;  Capitaines  and  Hert- 
lings's  process 112 


Xll  CONTENTS. 

PAGE 

Preparation  of  oxalic  acid  on  a  large  scale;  Preparation  of  the  mixed  lyes; 
Melting  apparatus    .         .         .         .         .         .         .         .         .         .         .113 

Mode  of  heating;  Contrivance  for  turning  the  mass  while  being  heated     .  114 
Working  up  the  melt;  Utilization  of  the  mother-lye.         ....  115 

Mode  of  obtaining  pure  oxalic  acid  from  the  crude  sodium  oxalate  .  .116 
Production  of  pure  oxalic  acid;  Pans  used  for  this  purpose  .  .  .117 
Production  of  an  almost  chemically  pure  product  .  .  .  .  .  118 

VII. 

VISCOSE  AND  VISCOID. 

Invention  of  these  products,  in  1892,  by  Brown,  Beadle  and  Cross;  Main 
point  of  the  invention;  Regulation  of  the  progress  of  the  conversion  of 
viscose  into  viscoid       .  .         .         .         ...        .         .  119 

Raw  material  for  the  preparation  of  viscose  solution;  Preparation  of  vis- 
cose for  experimental  purposes,  and  for  working  on  a  small  scale.         .  120 
Preparation  of  viscose  on  a  large  scale;  Material  for  this  purpose      .         .   121 
Comminution  of  the  cellulose,  and  apparatus  used;  Quantitative  propor- 
tions between  cellulose  and  caustic  soda;  Recognition  of  the  commence- 
ment of  the  formation  of  soda-cellulose.         .         .         .         .         .         .122 

Methods  used  in  practice  for  the  preparation  of  soda-cellulose.  .  .  123 
Soda-cellulose;  Main  point  in  the  manufacture  of  soda-cellulose;  Storing 

of  soda-cellulose .        .  :      .         .124 

Injurious  changes  in  soda-cellulose;  Advantages  of  storing  this  material  in 

an  ice-house .        .         .         .   125 

Products  formed  by  the  decomposition  of  soda-cellulose;  Preparation  of 

viscose;  Properties  of  carbon  disulphide 126 

Apparatus  for  the  preparation  of  larger  quantities  of  viscose;  Proportion 
between  soda-lye  and  carbon  disulphide;  Nature  of  cellulose  sulphocar- 

bonate 127 

Recovery  of  carbon  disulphide;  Preparation  of  viscose  solution        .         .  128 
Storing  viscose;  Vessels  used  for  this  purpose;  Stability  of  viscose;  Best 
temperature  for  preserving  viscose        .         .         .         .        .         .         .129 

Shipping  of  viscose;  Properties  of  viscose  solutions;  Recognition  of  the 
commencement  of  the  decomposition  of  a  viscose  solution;  Changes 
taking  place  in  viscose  solution     ........  130 

Influence  of  temperature  upon  the  decomposition  of  viscose  .  .  .  131 
Conversion  of  viscose  into  viscoid;  Chief  uses  of  viscose;  Preparation  of 

thicker  plates  from  viscoid 132 

Behavior  of  viscose  towards  metallic  salts;  Magnesium- viscose.         .         .  133 
Proportional  quantities  of  bodies  added  to  soda-viscose  for  the  purpose  of 
obtaining  other  varieties  of  viscose;  Preparation  of  viscose  according  to 

Cross 134 

Preparation  of  viscose  according  to  Seidel 135 

Transparent  plates  from  viscose 136 

Mode  of  giving  a  loosely- woven,  thin  tissue  the  appearance  of  a  close  and 
firm  fabric    .  .  137 


CONTENTS.  Xlll 


Preparation  of  chemically-pure  cellulose  sulphocarbonate  (viscose);  Uses 

of  viscose;  Incorporation  of  pulverulent  substances         .         -^o  •         •  138  —~ 

Use  of  viscose  in  the  manufacture  of  paper;  Ammonium  viscose         .         .  139 

Advantages  of  the  use  of  ammonium  or  magnesium  viscose;  Application 
of  viscose  as  a  size  to  wrapping  paper;  Table  showing  how  the  qualities 
of  the  papers  are  effected  by  the  addition  of  viscose  ....  140 

Viscose  in  the  manufacture  of  wall  paper;  Advantage  of  its  use  in  the 
manufacture  of  flock  paper;  Coating  of  ordinary  wall  paper  with  viscose; 
Imitations  of  leather  and  velvet  hangings  ......  141 

Viscose  in  cloth  printing;  White  design  upon  a  colored  ground         .         .  142 

Printing  color  prepared  with  viscose;  Viscose  solution  for  marking  fabrics 
in  mills,  and  as  a  substitute  for  ink  for  marking  household  linen,  etc.; 
Viscose  as  a  size  or  dressing 143 

Simplest  mode  of  sizing;  Addition  of  loading  agents  to  the  viscose;  Im- 
parting smoothness  and  lustre  to  the  tissue  treated  with  viscose  .  .  144  * 

Preparation  of  leather-like  bodies  by  means  of  viscose;  Constitution  of 
leather;  Main  point  in  the  production  of  a  satisfactory  imitation  of 
leather 145  * 

Fabrics  to  be  used  and  working  them  up  into  leather-like  masses;  Viscose 
solution  for  impregnating  the  tissues  .......  146 

First  step  in  the  operation;  Coloring  imitations  of  leather;  Vat  for  the 
viscose  solution;  Passing  the  fabric  through  the  viscose  solution  .  .  147 

Conversion  of  the  viscose  into  viscoid;  Protection  of  the  workmen  from 
the  gases  evolved;  Recovery  of  the  carbon  disulphide;  Finishing  and 
drying  the  fabrics.  ..........  148 

Working  thick  fabrics;  Condition  of  the  impregnated  fabrics;  Properties 
of  the  impregnated  fabrics 149 

Uses  of  fabrics  impregnated  with  cellulose;  Impregnation  of  ordinary 
pasteboard  with  viscose  solution  ........  150 

Uses  of  such  pasteboard;  Felt-plates  impregnated  with  viscose  solution, 
and  their  use  . .  .  .  .  151 

Viscose  in  the  manufacture  of  artificial  flowers;  Mode  of  application;  Pure 
viscose  for  especially  delicate  flowers  .  .  .  .  .  .  152 

Viscose  in  photography;  Preparation  of  films  from  viscose        .         .         .  153 

Viscoid  masses;  Preparation  of  homogeneous  viscose  masses  free  from 
bubbles  -  .  .  \  '  • 154 

Working  of  pure  viscoid;  Incorporation  of  foreign  bodies  with  the  viscose; 
Materials  for  the  preparation  of  white  masses;  Masses  of  a  pure,  milk- 
white  color  and  of  comparatively  slight  specific  gravity  .  .  .  155 

Experiment  on  a  small  scale  in  mixing  filling  substances  with  viscose       .  156 

Properties  of  a  viscoid  mass  of  the  proper  quality;  Preparation  of  larger 
quantities  of  viscoid  masses;  Mixing  or  kneading  machine  .  .  .  157 

Shape  of  a  kneading  and  mixing  paddle,  described  and  illustrated;  Mode 
of  working  the  viscose  solution  in  the  mixing  machine.  •  .  .  .  158 

Moulding  the  viscoid  mass,  and  moulds  used  for  the  purpose;  Moulding 

solid  and  hollow  articles;  Finishing  and  painting  the  articles         .         .  159     £ 


XIV  CONTENTS. 

PAGE 

Viscoid  masses  with  cellulose  or  mechanical  wood  pulp  as  filling  sub- 
stances and  their  various  applications  .  .  ...  .  .  160 

VIII. 

NITRO-CELLULOSE  ( GUN-COTTON,  PYROXYLIN). 

Combinations  formed  by  bringing  pure  cellulose  in  contact  with  nitric 
acid;  Two  distinctly  marked  groups  of  combinations;  Discovery  of  the 
combinations  formed  by  the  action  of  nitric  acid  upon  cellulose;  Former 
opinions  regarding  the  formation  and  composition  of  the  combinations.  161 

Modern  views  regarding  the  composition  of  gun-cotton;  Formation  of 
nitro-cellulose  .  .  .  '.  .;-•*  »  .  .  *  .  162 

Preparation  of  nitro-cellulose  in  explosive  as  well  as  soluble  form;  Investi- 
gations by  G.  Lunge  and  E.  Weintraub  .  .,  .  .  .  .  163 

Effect  of  the  presence  of  a  very  large  quantity  of  sulphuric  acid;  Use  of  a 
nitrating  fluid  containing  but  a  small  quantity  of  sulphuric  acid;  Time 
required  for  the  completion  of  the  process  of  nitration  .  ...  164 

Loss  in  cellulose  when  working  with  a  nitrating  fluid  heated  to  different 
degrees  of  temperature;  Change  in  the  structure  of  the  nitro-cellulose; 
Action  of  nitro-cellulose  towards  polarized  light  .  .  .  .  "  .  165- 

Main  objects  to  be  attained  in  practice  in  the  preparation  of  nitro- 
cellulose; Products  which  come  chiefly  into  question  for  practical  pur- 
poses   166 

Modes  of  calculating  the  nitrogen  in  nitro-cellulose  adopted  by  the  French 
chemists  and  by  the  English  and  German  chemists;  G.  Lunge  and  J. 
Bebie's  investigations;  Table  showing  the  relation  between  the  modes 
of  determination  adopted  by  the  French  and  German  chemists  .  .  167 

Table  showing  the  influence  exerted  by  the  content  of  water  in  the  acid 
mixture  upon  the  process  of  nitration  .  .  .  v  .  .  .  168 

Typical  soluble  nitro-cellulose — the  actual  collodion-cotton;  Solubility  of 
nitro-celluloses  .  .  .  .  .  .  .  .  ...  .  169 

Table  showing  the  effect  of  higher  temperatures  such  as  are  used  in  the 
preparation  of  collodion-cottons  .  .  .  .  .  .  .  .  1 70 

General  use  of  a  mixture  of  nitric  and  sulphuric  acids  for  the  preparation 
of  collodion-cotton;  Figures  obtained  with  the  use  of  1  nitric  acid  to  3 
sulphuric  acid  ...........  171 

Nitrating  fluids  used  in  the  experiments;  Table  showing  the  final  results 
of  further  experiments 172 

Importance  of  paying  attention  to  the  content  of  water  in  the  nitrating 
fluid;  Experiments  in  this  direction  .  .  .  .  .  .  .173 

Analyses  of  various  nitro-celluloses;  Preparation  of  gun-cotton;  First 
requisite  for  the  production  of  gun-cotton;  Purification  of  raw  cotton  .  174 

Acid  used  for  nitration;  Use  of  mixtures  of  concentrated  nitric  and  sul- 
phuric acids;  Former  mode  of  nitration;  Strength  of  nitric  acid  for  very 
explosive  products  and  for  readily  soluble  products  ....  175 


CONTENTS.  XV 

PAGE 

Sulphuric  acid  for  nitration;  Storage  of  the  acids;  Stoneware  vessels  for 
nitrating  purposes;  Constitution  of  the  nitrating  fluid  ....  176 

Proportions  of  acids  for  explosive  gun-cotton  and  for  soluble  gun-cotton 
or  collodion -cotton;  Condition  of  the  nitrating  fluid;  Importance  of  the 
constancy  of  the  composition  of  the  acid  mixture  .....  177 

Regeneration  of  the  nitrating  fluids;  Use  of  fuming  sulphuric  acid;  Execu- 
tion of  nitration 178 

Nitrating  apparatus,  described  and  illustrated.         .....  179 

Proportion  between  acid  and  cotton;  Time  required  for  nitration;  Use  of 
a  centrifugal  apparatus  for  effecting  nitration 181 

Washing  the  gun-cotton;  Ignition  of  gun-cotton  when  introduced  into  the 
washing  tank;  Construction  of  the  wash-tank 18$ 

Changes  in  gun-cotton ;  Measures  to  insure  the  removal  of  the  acid,  and 
comminution  of  the  gun-cotton  for  this  purpose;  Apparatus  used  .  .  184 

Separation  of  the  comminuted  gun-cotton  from  the  water        .        .         .  185 

Drying  the  gun-cotton;  Drying  upon  frames  covered  with  linen;  Gutt- 
mann's  plan  of  drying  gun-cotton;  Mode  of  heating  the  drying  room  .  186 

Hygroscopicity  of  dry  gun-cotton;  Mode  of  packing  gun-cotton;  Explosive 
gun-cotton,  and  mode  of  compressing  it  ......  187 

Compression  of  gun-cotton  for  loading  torpedoes;  Increasing  the  stability 
of  the  nitre-cellulose;  Manifestation  of  changes  in  the  product  .  .  188 

A.  Luck  and  C.  F.  Gross's  process  for  increasing  the  stability  of  nitro- 
cellulose; O.  R.  Schulz's  process  for  this  purpose 189 

Soluble  gun-cotton  or  collodion-cotton;  Great  importance  of  collodion- 
cotton  for  the  preparation  of  threads 190 

Influence  of  the  duration  of  the  action  of  the  acid  mixture  upon  the  cot- 
ton; Temperature  to  be  used  for  nitration;  Connection  between  the  solu- 
bility of  nitro-celluloses  and  the  content  of  nitrogen  in  the  products  .  191 

Characteristics  of  properly  prepared  collodion -cotton;  Disintegration  of 
the  nitro-combination;  Collodion-cotton  from  fine  tissue-paper  .  .  192 

Collodion;  Collodion  for  photographic  purposes;  Material  best  adapted 
for  the  preparation  of  collodion 193 

Composition  of  nitro-celluloses;  Cellulose  hexanitrate;  Cellulose  tetra- 
nitrate .  .  »  .  .  .  .  ' 194 

Cellulose  trinitrate;  Cellulose  dinitrate;  Behavior  in  drying  of  a  solution 
of  dinitro-cellulose  in  ether-alcohol;  Effect  of  an  admixture  of  dinitro- 
cellulose  upon  collodion  .  .  ...  .  .  .  .  .  195 

Neutralization  of  the  collodion-cotton;  Preparation  of  the  solution;  Influ- 
ence of  the  physical  condition  of  collodion-cotton  upon  its  solubility; 
Mode  of  keeping  collodion-solution  .  .  .  .  •  «  .  196 

Elastic  masses  from  nitro-cellulose  (artificial  rubber);  Production  of 
masses  from  nitro-cellulose  possessing  considerable  elasticity;  Fluids 
which  may  be  used  for  this  purpose  .  .  *  •  .  .  .  197 

Mechanical  manipulation  of  the  mass;  Most  suitable  solvent;  Recovery  of 
the  volatile  solvent;  Further  manipulation  of  the  mass.  ...  •'  .  198 

Nature  of  the  masses  finally  obtained;  Mixing  the  masses  with  indifferent 
bodies;  Inflammability  of  the  masses  and  mode  of  reducing  it  .  .  199 


XVI  CONTENTS. 

PAGE 

Cellulose  esters;  Cellulose  acetic  ester  .  .  .  •  \_?  •  •  200 
Composition  of  cellulose  tetra-acetate,  and  its  indifference  towards  the 

action  of  chemicals        .        .         .         ...         .     '    .        .         .  201 

Applications  of  cellulose  acetic  ester;  Preparation  of  an  acetyl  derivative 

of  cellulose  according  to  L.  Lederer  .  .  .  •  .  .  .  .  202 
Cellulose  butyric  ester;  Other  similar  combinations;  "Solid  spirit;"  Mode 

of  bringing  alcohol  into  a  solid  form      .         .         .         ....  203 

IX. 

ARTIFICIAL  SILK. 

Source  of  natural  silk;  Composition  of  raw  silk;  Scouring  or  boiling  raw 
silk  .  205 

Appearance  of  silk  under  the  microscope;  Early  efforts  to  produce  artifi- 
cial silk;  Varieties  of  artificial  silk  .  .,...'.  206 

Historical  development  of  the  artificial-silk  industry;  Credit  due  to  M.  de 
Chardonnet;  Du  Vivier's  and  Lehner's  processes;  A.  Millar's  method; 
Hummel's  process  .  .  .  .  .  ...  .  .  207 

Cadoret's  method;  Difference  between  the  methods  according  to  which 
textile  threads  are  prepared  from  pure  cellulose  and  from  nitro-cellu- 
lose;  Invention  of  Dr.  Hermann  Pauldy;  Process  proposed  by  Langhaus.  208 

Cheapness  and  safety  of  the  preparation  of  silk-like  threads  from  viscose 
solution;  Chardonnet  artificial  silk;  Chardonnet's  original  patent  for 
preparing  textile  threads .  .  209 

Details  of  the  practical  application  of  Chardonnet's  process;  Nitration  of 
the  cotton 210 

Nitrating  vessels;  Time  required  for  nitration 211 

Physical  behavior  of  the  nitrated  cotton;  Physical  examination  of  the 
nitrated  cotton;  Eesults  of  Chardonnet' s  comparative  experiments  .  212 

Removal  of  acid  from  the  cotton;  Washing  the  nitrated  cotton;  Prepara- 
tion of  the  collodion  solution 213 

Solvent  used;  Time  required  for  solution;  Filtering  the  solution  and  filter 
for  the  purpose 214 

Storing  the  solution;  Spinning  the  collodion;  Disposition  of  the  spinning 
apparatus;  Mode  of  making  the  glass  spinners  .  .  .  .  .  215 

Arrangement  of  the  spinners;  Reeling  up  the  threads;  Removal  of  the 
vapors  of  alcohol  and  ether  from  the  spinning  room  ....  216 

Chacdonnet's  spinning  apparatus,  described  and  illustrated       .         .         .   217 

Condensing  vessels;  Throwing  or  twisting  the  individual  threads;  Inflam- 
mability of  artificial  silk;  Denitration  .......  219 

Mode  of  effecting  denitration;  Composition  of  denitrating  fluids;  Use  of 
ammonium  sulphide  for  the  purpose,  and  its  preparation;  Recognition 
of  the  correct  composition  of  the  denitrating  fluid  ....  220 

Bleaching  the  silk;  Preparation  of  colored  artificial  silk;  Direct  coloring 
of  the  silk  while  in  the  course  of  preparation;  Mixture  of  the  coloring 
matter  with  the  collodion  .....  221 


CONTENTS.  XV11 

PAGE 

Dyeing  the  finished  silk;  Du  Vivier's  artificial  silk  ....  222 
Method  of  nitration  by  means  of  dry  saltpetre  and  sulphuric  acid;  Solvent 

for  the  nitro-cellulose    ..........  223 

Lehner's  artificial  silk;  Solvent  for  the  nitro-cellulose;  Modification  of 

Lehner's  process 224 

Denitration  of  artificial  silk;  H.  Eichter's  investigations  regarding  this 

subject;  Pith  of  Richter's  method;  Cuprous  chloride  for  denitration  .  225 
Special  advantage  claimed  for  Richter's  process;  Recovery  of  the  nitrogen 

compounds;  Recovery  of  the  oxy-salts  .......  226 

A.  Peit's  method  for  the  preparation  of  artificial  silk;  Drawbacks  of  the 

process  of  producing  artificial  silk   from  nitro-cellulose;  Spontaneous 

ignition  of  nitro-cellulose       .........  227 

X. 

CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK  AND  LUSTRA- 
CELLULOSE). 

Methods  for  the  conversion  of  cellulose  into  a  solution  from  which 
artificial  textile  threads  may  be  produced;  Advantages  of  the  process; 
Use  of  cuprammonium  as  solvent  for  cellulose 229 

Dr.  Pauly's  artificial  silk;  Operation  for  the  production  of  the  thread; 
Purification  of  the  cotton 230 

Dissolving  the  cotton  in  cuprammonium;  Apparatus  for  the  purpose        .  231 

Judging  the  progress  of  solution  by  samples     ......  232 

Filtration  of  the  solution  and  filter  used  for  the  purpose  ....  233 

Spinning  the  solution;  Construction  of  the  contrivance  in  which  the 
formation  of  threads  is  effected;  Arrangement  of  the  spinners;  Col- 
lector for  the  threads  ........  .  234 

Washing  the  threads;  Further  manipulation  of  the  threads  by  mechani- 
cal means;  Properties  of  cellulose  artificial  silk  .....  235 

E.  Bronnert's  process  for  the  preparation  of  textile  threads;  Conversion 
of  cellulose  into  soda-cellulose;  Use  of  the  substances  according  to 
molecular  weights  ..........  236 

Preparation  of  cuprammonium:  Removing  the  turbidity  of  the  solution; 
Filtering  the  solution  .  .  .  .  ...  .  .  .  .  237 

Conversion  of  cupric  hydroxide  into  cuprammonium,  and  apparatus 
employed  ...  •  .  .  .  .  .  .  .  .  238 

Preparation  of  cuprammonium  solution  according  to  the  process  of  E. 
Bronnert,  M.  Fremery  and  J.  Urban 239 

Recovery  of  the  copper;  Various  methods  for  this  purpose        .         .         .  240 

Artificial  silk  according  to  M.  Fremery  and  J.  Urban;  Manner  of  drying 
the  thread;  Phases  in  the  drying  process  .  .  .  .  .  .  242 

Composition  of  the  fluid  used  for  the  decomposition  of  the  cellulose  solu- 
tion; Explanation  of  the  effect  of  concentrated  sulphuric  acid  .  .  243 

Artificial  horse  hair,  its  production  and  uses     ......  244 


XV111  CONTENTS. 

PAGE 

XL 

TEXTILE  THREADS  FROM  VISCOSE  (THREADS  FROM  LUSTRA -CELLLULOSE). 
Coagulation  of  viscose  solution;  Simplicity  of  the  process  of  obtaining  pure 
cellulose  from  viscose;   Experiments  in  making  textile  threads  from 
viscose.          .        .        .        •«.        .       ...        .         .        .  •       .         .  246 

Properties  of  viscose  threads;  Cost  of  producing  threads  from  viscose        .  247 
Preparation  of  perfectly  clear  viscose  solution,  and  apparatus  employed    .  248 
Filtering  the  solution,  and  filter  used;  Spinning  apparatus        .         .         .  249 
Treatment  of  the  threads  emerging  from  the  spinning  apparatus       .         .  250 
Importance  of  using  viscose  solution  of  the  same  temperature  .  .  251 
Regulation  of  heat;  Preparation  of  textile  threads  according  to  Stearn; 
Preparation  of  long,  narrow  strips  for  taking  pictures  for  the  cinemato- 
graph           ...        .  252 

Millar's  artificial  silk  (gelatine  silk)     .         .         ...'..         .253 

Depriving  gelatine  threads  of  their  brittleness;  General  properties  of  textile 
threads  produced  by  artificial  means;  Lustre  of  artificial  silk;  Effect  of 
water  on  artificial  threads     .         .         .         .        .         ...         .  254 

Facts  to  be  taken  into  consideration  in  dyeing  threads  of  artificial  silk; 
Microscopical  examination  of  artificial  textile  threads;  Difference  be- 
tween natural  and  artificial  silks .255 

Table  showing  diameters  of  various  kinds  of  silks;  Optical  phenomena  ex- 
hibited by  natural  and  artificial  silks;  Tenacity  of  artificial  silk  as  com- 
pared with  natural  silk.         .         .         .        .        .        .        .  .  256 

Dr.  Hassack's  investigations;  Moisture  and  hygroscopicity  of  artificial 
silks;  Specific  gravity  of  artificial  silks  .         .        .        .        .r      .        .  257 

Elasticity  and  tenacity  of  artificial  silk;  Eesults  of  tests    .         .         .        .258 

Behavior  of  artificial  silk  in  a  chemical  respect;  Principal  difference  be- 
tween the  various  kinds  of  artificial  silk        .         .         .         ...  259 

Microscopical  examination  of  artificial  silk  with  the  use  of  reagents.         .  260 
Distinction  between  cellulose  and  nitro-cellulose  silks       ._„•.,»        •  261 

XII. 

CELLULOID. 

Invention  of  celluloid  by  Hyatt,  of  Newark,  N.  J. ;  Properties  of  cellu- 
loid; Nature  of  celluloid 263 

Methods  for  the  preparation  of  celluloid;  Value  of  the  separate  methods  .  264 
Classification  of  the  methods  used  for  the  manufacture  of  celluloid;  Prep- 
aration of  the  collodion-cotton       ........  265 

Material  used  according  to  the  original  statements  by  Hyatt;  Preparation 
of  celluloid  according  to  Hyatt      ........  266 

Preparation  of  celluloid  according  to  Tribouillet  and  Besancele        .         .  268 
Preparation  of  celluloid  with  alcoholic  camphor  solution  ....  269 

Preparation  of  celluloid  according  to  Magnus  ......  270 

Mode  of  preparing  the  solution  of  dry  collodion-cotton;  Preparation  of 


CONTENTS.  XIX 

PAGE 

celluloid  with  recovery  of  the  solvent;  Description  of  a  process  which 
can  be  practically  applied      .........  271 

Manner  of  testing  freshly-prepared  collodion-cotton;  Requisites  of  collod- 
ion-cotton which  is  to  be  dissolved 272 

Drying  the  collodion-cotton ;  Apparatus  in  which  the  solution  of  collod- 
ion-cotton and  camphor  is  effected,  and  manner  of  working  with  it; 

Solvent  to  be  used 273 

Advantages   of  anhydrous   ether  as  a  solvent;    Recovery  of  the   ether 
evaporating  from  the  fluid  celluloid  mass       ......  274 

Apparatus  for  preparing  the  solution;  Trays  for  solidifying  the  solution, 
described  and  illustrated       .........  275 

Apparatus  for  condensing  the  ether-vapors,  described  and  illustrated        .  276 

Removing  the  finished  celluloid  from  the  trays 278 

Drying  chamber;  Heating  celluloid  to  be  rolled        .....  279 

Properties  of  celluloid;  Nature  of  celluloid  at  the  ordinary  temperature    .  280 
Mode  of  rendering  celluloid  plastic  by  heating;  Spontaneous  decomposi- 
tion of  celluloid;  Inflammability  of  celluloid.         .....  281 

Behavior  of  celluloid  towards  solvents;  Physical  properties  of  celluloid; 

Example  of  the  great  tenacity  and  elasticity  of  celluloid         .         .         .  282 
Working  celluloid;  Mechanical  manipulation  of  celluloid;  Rolling  cellu- 
loid        283 

Coloring  celluloid;  Employment  of  tar  colors  for  this  purpose;  Coloring 
transparent  celluloid  articles;  Production  of  articles  from  the  colored 

material 284 

Production  of  certain  color  effects;  Red  and  scarlet  .....  285 

Blue;  Indigo-blue;  Berlin-blue;  Violet;  Brown;  Gray;  Black    .         .         .286 
Printing  on  celluloid;  Preparation  of  a  celluloid-plate  for  printing;  Pro- 
cess for  providing  celluloid  articles  with  colored  pictures       .         .         .  287 
Transferring  pictures  to  celluloid;  Mode  of  protecting  the  pictures  .         .  288 
Printing  on  celluloid  in  the  same  manner  as  pictures,  in  many  colors,  are 
produced  on  paper;  Preparation  of  gutta-percha  printing  blocks;  Cellu- 
loid with  filling  masses.         .........  289 

Milk-white  bodies;  Imitation  of  white  marble;  Materials  used;  Celluloid 

masses  of  light  weight 290 

Methods  for  combining  the  pulverulent  filling  substance  with  the  cellu- 
loid; Coloring  filled  celluloid  masses;  Imitation  of  ivory        .         .         .  291 
Imitation  of  tortoise-shell        .         .        .         .        ...         .         .         .  292 

Moulding  celluloid  articles;  Heating  apparatus  for  the  purpose,  described 

and  illustrated 293 

Manufacture  of  celluloid  tubes;  Joining  two  pieces  of  celluloid.        ."       .  294 
Shaping  celluloid  by  pressing;   Imitations  of  corals;    Manufacture  of 
combs;  Cliches  from  celluloid        .         .         .         .         ...         .295 

Method  of  making  a  plaster  of  Paris  cast;  Celluloid  stamps      .         .         .  296 
Collars  and  cuffs  from  celluloid;  White  masses  for  this  purpose;  Making 
the  mould;  Cleaning  celluloid  collars  and  cuffs      .         .        .        .         .  297 

Celluloid  for  dentists'  use        .....  .  298 


XX  CONTENTS. 

PAGE 

Coloring  celluloid  with  cinnabar;  Mode  of  making  the  plates;  Tempera- 
ture to  which  the  celluloid  has  to  be  heated.  ...  .  .  299 

Objects  of  art  from  celluloid;  Metals  used  for  incrustations;  Finishing  the 
incrusted  plate;  Bending  incrusted  plates  ..."...  300 

Celluloid  mosaics;  Imitation  of  lapis  lazuli,  and  of  variegated  marble;  Pro- 
duction of  mosaics;  Execution  of  the  design.  .....  301 

Celluloid  lacquer;  Use  of  celluloid  lacquer  for  coating  maps,  copper  and 
steel  engravings  and  drawings  .  ...  .  ...  .  302 

Protecting  metals  from  rust;  Basis-material  of  all  celluloid  lacquers;  Names 
under  which  celluloid  lacquers  are  brought  into  commerce  .  .  .  303 

Preparation  of  an  excellent  celluloid  lacquer    .         .        .         .         .        .  304 

Effects  produced  with  colored  celluloid  lacquers;  Conservation  of  metals 
by  means  of  celluloid  lacquer;  Special  importance  of  a  coating  of  cellu- 
loid lacquer  for  metallic  articles  which  come  in  contact  with  sea  water.  305 

Protection  of  iron  vessels  from  the  action  of  sea  water;  Celluloid  masses 
without  an  addition  of  camphor;  Use  of  naphthaline  .  .  .  .  306 

Substitutes  for  camphor  proposed  by  Zuhl  and  Eisemann,  and  by  J.  R. 
Goldsmith 307 

XIII. 

RUBBER  COMPOUNDS. 
Definition  of  rubber  compounds;  Principal  substances  used  as  additions  to 

rubber 309 

Advantages  of  coal-tar  pitch;  Plastite  masses,  and  their  nature        .         .  310 
Composition   of  plastite    masses,  and  their  preparation;  Elastic  rubber 
masses  .............  311 

Balenite,   its  composition   and   preparation;  Uses  of  balenite;  Rubber- 
leather;  Properties  and  preparation  of  rubber-leather  .         .         .         .312 

Cost  of  producing  rubber-leather;  Marine  glue,  and  definition  of  this  term.  313 
Mode  of  applying  marine  glue;  Preparation  of  a  lacquer  from  marine  glue.  314 

XIV. 

RUBBER  SUBSTITUTES. 

Increasing  demand  for  rubber;  Groups  of  rubber  substitutes;  Steenstrup's 
method  for  the  preparation  of  a  rubber  substitute.         ....  315 

Importance  of  actual  rubber  substitutes,  and  their  preparation  by  the 
treatment  of  oils;  Oil-rubber;  Drying  and  non-drying  oils;  First  step 
in  the  manufacture  of  oil-rubber        .         .         .         .         .         .         .316 

Heating  the  oil;? Test  as  to  whether  the  oil  has  been  sufficiently  heated; 
Cooling  the  oil  .         .         .         .         .         .         .         .  '      .         .  317 

Oxidation  of  the  oil  with  nitric  acid;  Nature  of  the  oil-rubber  obtained    .  318 
Restoring   old   oil-rubber;  Uses  of  oil-rubber;  Manufacture  on   a   large 
scale  of  oil-rubber  by  means  of  thick  oil         ......  319 

Apparatus  for  oxidizing  the  oil,  described  and  illustrated          .         »         .  320 


CONTENTS.  XXI 

PAGE 

Time  required  for  thickening  the  oil;  Working  the  thick  oil  .  .  .  321 
Use  of  oil-rubber  for  securing  large  panes  of  glass  in  frames;  Factis 

masses,  and  their  nature        .........  322 

Sulphured  oils  (brown  and  black  factis)  and  their  preparation  .  .  323 

Substances  which  may  be  added  to  oil-rubber;  Vulcanized  oil,  and  its 

preparation  ............  324 

White  factis;  R.  Henriquez's  investigations 325 

Oils  used  for  the  production  of  factis,  and  quantities  of  disulphur  dichlor- 

ide  required  for  their  manipulation  .  .  .  r*^ .  .  .  .  326 
Vessels  for  the  oxidation  of  the  oils;  Boilers  for  the  preparation  of  factis.  327 
Mode  of  mixing  factis  with  genuine  rubber;  Sulphuretted  hydro-cellulose 

as  rubber  substitute,  and  its  preparation  according  to  Sthamer  .  .  328 
Preparation  of  disulphur  dichloride,  and  apparatus  used,  described  and 

illustrated '«.":/^i*»j  .329 

Preparation  of  pure  disulphur  dichloride  for  experimental  purposes  .  330 
Necessity  of  exercising  care  in  handling  disulphur  dichloride  .  .  .  331 
Index  .  333 


OF  THE 

UNIVERSITY 

OF 


CELLULOSE,  CELLULOSE  PRODUCTS, 
AND  RUBBER  SUBSTITUTES. 


CELLULOSE. 

THE  substance  to  which  the  term  cellulose  has  been 
applied  is  very  widely  distributed  throughout  nature,  it 
forming  the  structural  basis  of  all  vegetable  organisms. 
All  plants,  from  the  unicellular  bacterium  up  to  the  mam- 
moth conifers  of  California,  are  built  up  of  cells,  the  en- 
velopes or  walls  of  which  consist,  in  every  case,  of  one  and 
the  same  body,  namely,  cellulose.  In  the  higher  plants 
the  individual  contiguous  cells  coalesce  in  such  a  way  that, 
in  certain  places,  their  walls  are  broken  up,  tubular  struct- 
ures— the  so-called  vessels — which  frequently  attain  extra- 
ordinary lengths,  being  thereby  formed.  There  are  vessels 
which  extend  from  the  roots  to  the  tops  of  gigantic  trees, 
and,  as  above  stated,  have  been  formed  by  the  coalescence 
of  individual  cells  of  a  more  or  less  globular  form. 

While  in  many  plants  the  cells,  as  well  as  the  vessels 
formed  from  them,  always  remain  soft,  in  others  combina- 
tions are  deposited  in  them  by  which  the  cellulose  is 
changed  in  a  characteristic  manner,  the  walls  of  the  vessels 
frequently  acquiring  considerable  firmness ;  and  the  cellu- 
lose vessels  are  changed  to  wood-vessels.  In  herbaceous 
plants  such  a  transformation  does  not  take  place,  and 
hence  they  have  to  be  sharply  distinguished  from  the 


2  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

wood-forming  plants,  and  the  process  of  the  formation  of 
wood  will  have  to  be  more  closely  discussed. 

OCCURRENCE    OF    CELLULOSE. 

While  formerly  the  opinion  prevailed  that  cellulose  oc- 
curs exclusively  in  the  vegetable  organism,  more  recent 
investigations  have  also  shown  its  presence,  though  to  a 
limited  extent,  in  the  animal  kingdom,  its  occurrence  in 
many  Tunicata  having  been  definitely  established,  and  it 
has  also  been  found  in  insects  and  other  articulates.  Its 
occurrence  in  the  skins  of  snakes  has  not  been  finally 
proved.  It  is  also  claimed  that  cellulose  is  formed  in  the 
human  organism  during  certain  morbid  processes  (tubercu- 
losis). However,  such  occurrences  are  of  minor  importance, 
all  the  cellulose  made  use  of  being  exclusively  derived  from 
plants.  Formerly  we  had  to  content  ourselves  with  such 
quantities  of  cellulose  as  were  in  a  quite  pure  state  at  our 
disposal  in  the  form  of  vegetable  wool  and  the  fibres  of 
textile  plants,  but  the  demand  for  cellulose  having  ac- 
quired colossal  dimensions  by  reason  of  the  enormous  in- 
crease in  the  consumption  of  paper,  efforts  had  to  be  made 
to  open  up  other  sources  of  it. 

Attention  was  first  directed  towards  straw  as  a  material 
for  the  preparation  of  cellulose,  because  it  was  supposed  that 
its  vessels  having  been  only  slightly,  or  not  at  all,  converted 
into  wood,  the  cellulose  could  without  much  difficulty  be 
obtained  in  a  sufficiently  pure  state.  However,  it  was  left 
out  of  consideration  that  the  stalks  of  grasses,  which  in  a 
dry  state  form  the  material  termed  straw,  contain  consider- 
able quantities  of  silica  and,  in  many  cases,  are  provided 
with  what  may  be  called  a  siliceous  armor.  This  fact 
frustrated  for  a  long  time  every  attempt  to  prepare  from 
straw  cellulose  which  might  at  least  be  available  for  the 
manufacture  of  paper.  Although  successful  processes  for 
the  treatment  of  straw  for  paper-making  were  finally  intro- 
duced, the  pulp  obtained  as  well  as  the  papers  manufac- 


CELLULOSE.  6 

tured  from  it,  showed  so  many  defects  that  this  mode  of 
obtaining  cellulose  was  soon  again  abandoned. 

The  employment  of  wood  for  the  successful  preparation 
of  cellulose  in  a  pure  state,  and  in  any  quantities  desired,  is 
an  achievement  of  modern  times,  no  attempt  having  been 
formerly  made  to  utilize  this  material  for  the  purpose. 
Chemically,  wood  is  nothing  but  cellulose  which  has  under- 
gone certain  changes.  Originally,  every  kind  of  wood  is 
cellulose,  and  in  genuine  woody  plants  there  is  always 
found  around  the  stalk  a  growing  annular  layer  which,  in 
accordance  with  its  nature,  has  to  be  designated  as  cellu- 
lose. This  annular  layer,  to  which  the  term  liber  has  been 
applied,  is  formed  anew  in  every  period  of  vegetation,  and 
in  the  next  and  succeeding  periods  of  vegetation  it  is  grad- 
ually transformed  into  wood. 

This  transformation  is  effected  by  various  bodies,  known 
by  the  general  term  of  encrusting  substances,  becoming  im- 
bedded in  the  cellulose  mass.  By  this  encrustation  the 
originally  thin  walls  of  the  vessels  of  which  the  liber  con- 
sists, become  thicker,  more  solid,  acquire  a  dark  coloration, 
and  are  finally  transformed  into  wood-vessels  of  consider- 
able strength  and  tenacity,  extraordinarily  great  in  some 
varieties  of  wood. 

The  encrusting  substances  of  the  wood  possess  the  prop- 
erty of  being  destroyed  or  dissolved  by  various  chemicals, 
while  the  cellulose  is  not  at  all,  or  but  slightly,  attacked  by 
them.  Hence  by  one  or  the  other  of  the  processes  to  be 
fully  described  later  on,  a  cellulose  is  obtained  which,  when 
sufficient  care  has  been  taken  in  purifying  it,  may  be  called 
chemically  pure,  i.  e.,  free  from  all  foreign  bodies. 

COTTON. 

Cellulose  as  found  in  nature  is  never  chemically  pure,  it 
containing  in  addition  a  series  of  other  combinations.  In 
its  purest  state  it  occurs  in  the  vegetable  structures  known 
as  hair  or  wool.  As  a  rule,  each  hair  consists  of  a  mem- 


4  CELLULOSK,  AND    CELLULOSE    PRODUCTS. 

branous  cell,  frequently  of  considerable  length,  the  wall  of 
which  is  formed  of  cellulose,  admixed,  however,  with  certain 
salts,  nitrogenous  combinations,  and,  in  some  cases,  with 
coloring  matter. 

Cotton  is,  unquestionably,  the  most  important  of  all  the 
vegetable  wools.  It  is  the  product  of  several  species  of  the 
genus  Gossypium  of  the  Natural  Order  Malvaceae  or  Mallows. 
The  cotton  plant  has  from  time  immemorial  been  cultivated 
in  tropical  countries.  The  cotton  is  found  in  the  fruit  of 
the  plant,  and  actually  is  the  hairs  or  fibres  growing  around 
the  seed  and  attached  to  it.  This  attachment  of  the  hairs  or 
fibres  to  the  seed  is  typical  of  the  genus.  The  fruit,  Fig.  1, 
known  as  boll,  consists  of  a  capsule  or  pod  divided  by  mem- 
branes into  three  or  five  cells.  It  bursts  at  the  time  of 
maturity  and  the  hairs  or  fibres  protrude  from  it  in  the  form 
of  a  compact  ball  of  a  white  or  yellow  color.  The  seeds  are 

the  size  of  a  pea  and  the  cotton 
fibres  are  separated  from  them  by 
means  of  special  mechanical  con- 
trivances. 

Viewed  under  the  microscope,  the 
cotton  fibre  appears  as  a  hollow 
cylinder,  one  end  of  which  is  pointed 
and  closed,  while  the  other  end,  by 
means  of  which  it  was  attached  to 
the  seed,  is  irregularly  torn.  Cotton 
is  the  more  highly  valued  the  thin- 
ner the  individual  fibres  are,  the 
more  uniformly  smooth  they  appear 
under  the  microscope,  and  the  more 
closely  their  form  approaches  that 

of  a  cylinder.     Fig.  2  shows  cotton 
Fruit  of  the  Cotton  Plant.    _,         \.   ,,  -c  i        *  -n 

fibres   highly    magnified.     As    will 

be  seen  from  the  illustration,  the  individual  fibres  are  more 
or  less  strongly  twisted  and  smooth,  but  with  the  use  of  a 
very  high  magnifying  power  they  appear  obliquely  striate. 


CELLULOSE.  O 

f 

The  length  of  the  cotton  fibre  varies  between  0.391  and 
1.575  inches,  and  its  diameter  between  0.0004  and  0.0016 
inch.  In  fine  qualities  of  cotton  the  cavity  or  lumen  of  the 
fibre  is  quite  narrow,  while  in  coarser  varieties  it  is  three 
or  four  times  the  size  of  the  cell-wall ;  in  unripe  fibres  it  is 
sometimes  entirely  wanting.  Like  the  striation  of  the 
fibre,  its  cuticle  can  be  plainly  recognized  only  with  a  very 
high  magnifying  power. 

FIG.  2. 


Cotton  Fibres. 

F,  cotton  filaments ;  d,  places  of  twist ;  g  C,  granulated  cuticle ;  Z,  cavity  or 
lumen  ;   Q,  cross  sections. 

The  value  of  a  variety  of  cotton  is  determined  by  two 
factors,  namely,  the  length  and  diameter  of  the  individual 
fibres ;  the  longer  the  fibres  are  and  at  the  same  time  the 
smaller  their  diameter  is,  the  more  valuable  the  cotton. 
Cotton  with  fibres  less  than  0.984  inch  long  is  called  short- 
staple  as  distinguished  from  long-staple,  the  fibres  of  which 
may  reach  a  length  of  up  to  2.362  inches.  With  regard  to 
the  diameter  of  the  fibres,  eight  different  grades  of  fineness 
are  distinguished  in  commerce,  the  limits  of  diameter  for 
the  respective  classes  being  from  0.0004  to  0.0016  inch. 


6  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

According  to  numerous  analyses,  the  chemical  composi- 
tion of  cotton  is  as  follows :  Cellulose  87  to  91  per  cent., 
water  5.2  to  8.0  per  cent.,  fat  and  wax  0.4  to  0.5  per  cent., 
nitrogenous  bodies  (remains  of  protoplasm)  0.5  to  0.7  per 
cent.,  ash  0.1  to  0.13  per  cent. 

In  addition  to  cotton,  there  are  numerous  other  plants 
producing  fibres  consisting  largely  of  cellulose,  and  which 
are  also  used  as  textile  fibres.  Among  them  may  be  men- 
tioned the  fibres  of  the  various  species  of  Bombax  or  wool 
tree,  and  of  the  different  varieties  of  Asclepias,  but  they  are 
far  behind  cotton  in  technical  importance. 

Other  natural  sources  of  cellulose-fibres  are  the  bast  of  a 
large  number  of  plants,  and  finally  the  fibres  obtained  by  a 
special  process  (retting)  from  the  stalks  and  leaves  of  many 
plants.  As  the  most  important  of  these  may  be  mentioned  : 
flax,  hemp,  various  kinds  of  nettle,  jute,  aloe,  Manila  hemp, 
New  Zealand  flax,  etc.  For  the  purpose  of  preparing  from 
cotton  a  cellulose  which  may  be  considered  chemically  pure, 
white  cotton  is  first  for  some  time  extracted  with  ether  to 
dissolve  the  entire  quantity  of  fat  and  wax  present.  It  is 
then  repeatedly  boiled  with  soda  lye,  which,  however, 
should  not  be  too  concentrated,  whereby  the  nitrogenous 
combinations  are  brought  into  solution.  Very  dilute  hy- 
drochloric acid  is  then  poured  over  the  cotton  and  the 
whole  gently  heated,  the  operation  being  continued  for 
some  time.  Finally  the  cotton  is  treated  with  water  till  the 
last  traces  of  acid  have  disappeared.  When  incinerated, 
cotton,  which  has  been  sufficiently  purified,  should  leave 
no  residue. 

PROPERTIES  OF  CELLULOSE. 

Cellulose,  purified  in  the  manner  given  above,  remains 
unchanged  as  regards  its  structure,  chemicals  when  used  in 
sufficiently  dilute  state  having  no  effect  upon  it.  The 
elementary  analysis  of  cellulose  leads  to  the  formula 
C12H2o010.  However,  this  formula  actually  expresses 


CELLULOSE.  7 

only  its  elementary  composition,  and  the  actual  formula 
wojild  probably  correspond  to  quite  considerable  multiples 
of  the  numbers  above  mentioned. 

As  regards  the  percentage  composition,  cellulose  agrees 
with  a  very  large  number  of  other  bodies  which  frequently 
occur  in  plants.  Thus,  it  has,  for  instance,  the  same  com- 
position as  starch,  gum,  gum-like  substances,  dextrin,  etc. 
These  bodies  form  a  large  group  of  isomeric  combinations, 
they  having  the  same  percentage  composition,  but  exhibit- 
ing different  physical  and  chemical  properties. 

There  can  be  no  doubt  that  in  the  living  plant-organism 
these  bodies  may  constantly  be  transformed  one  into  the 
other,  incontestable  proof  of  this  fact  being  furnished  by 
the  bulbs  and  tubers  of  many  plants.  In  the  cells  of  such 
bulbs  and  tubers  large  quantities  of  starch  are  stored  up, 
but  as  the  development  of  the  plant  progresses,  the  quan- 
tity of  starch  decreases  more  and  more,  it  being  largely 
transformed  into  cellulose,  gum,  etc.  Since  cellulose  may 
be  converted  into  soluble  combinations  by  the  acids  formed 
in  plants,  it  would  not  seem  improbable  that,  in  the  higher 
plants,  the  chemical  process  takes  place  in  such  a  way  that 
a  very  large  number  of  non-nitrogenous  compounds  occur- 
ring in  plants  may  be  directly  or  indirectly  formed  from 
these  combinations. 

It  would  also  seem  very  probable  that  the  acids  and  fer- 
ments, which  appear  during  the  digestion  of  nutriment  in 
the  stomach,  possess  the  property  of  transforming  cellulose 
into  soluble  combinations,  because  many  animals  can  digest 
considerable  quantities  of  cellulose,  it  forming  a  very  im- 
portant fodder  for  them.  While  formerly  the  opinion  pre- 
vailed that  cellulose  is  absolutely  indigestible  for  carniv- 
orous animals  and  human  beings,  recent  researches  have 
shown  such  not  to  be  the  case  and  that  the  human  stomach 
is,  after  all,  capable  of  digesting  quite  remarkable  quanti- 
ties of  it. 


8  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

SOLUBILITY  OF    CELLULOSE. 

'Cellulose  is  insoluble  in  ordinary  solvents,  such  as  water, 
alcohol,  ether,  etc.,  and,  without  undergoing  a  change, 
actually  dissolves  only  in  ammoniacal  solution  of  cupric 
oxide.  When  brought  in  contact  with  such  a  solution,  the 
fibres  first  swell  up  very  much,  and  solution  is  then  grad- 
ually effected.  On  mixing  the  solution  with  alcohol  or 
sugar  solution,  or  neutralizing  it  with  an  acid,  the  cellulose 
is  precipitated  in  colorless  flakes,  retaining,  however,  its 
original  chemical  properties. 

Formerly  no  other  solvent  for  cellulose  than  ammoniacal 
solution  of  cupric  oxide  was  known,  but  towards  the  end  of 
the  19th  century  a  body  also  capable  of  dissolving  it  was 
found  in  the  alkaline  sulphocarbonates.  Solutions  of  cellu- 
lose prepared  according  to  this  method  exhibit  peculiar 
properties  which  will  without  doubt  insure  their  extensive 
application  in  various  branches  of  industry.  As  an  exam- 
ple may  here  be  mentioned  that  textile  threads  may  be  pre- 
pared from  such  a  cellulose  solution. 

The  behavior  of  cellulose  towards  the  action  of  chemical 
agents  is  of  great  importance  since  a  series  of  combinations 
of  considerable  industrial  interest  may  thus  be  formed. 

BEHAVIOR    OF    CELLULOSE    TOWARDS    WATER. 

At  the  ordinary  temperature  water  has  no  effect  what- 
ever upon  cellulose.  In  boiled  water  pure  cellulose  may  be 
kept  for  any  length  of  time  without  suffering  any  change. 
If,  however,  moist  cellulose  be  exposed  to  the  air,  the  com- 
mencement of  a  change  will  in  a  short  time  be  observed, 
the  originally  white  mass  turning  gray,  becoming  constantly 
darker  and  finally  acquiring  the  appearance  of  the  black- 
brown  mould  found  in  the  rotten  core  of  trees.  A  micro- 
scopical examination  of  such  altered  cellulose  shows  it  to 
contain  innumerable  bacteria  which,  in  appearance,  closely 
resemble  those  found  in  wood  mould.  This  destructive 
process  in  cellulose  is  very  probably  similar  to  that  which 


CELLULOSE.  9 

takes  place  in  the  decay  of  wood,  if  not  entirely  identical 
with  it. 

That  cellulose  belongs  to  the  readily  changeable  com- 
binations is  shown  by  the  fact  that  at  a  higher  temperature 
it  is  noticeably  affected  by  water.  By  boiling  pure  cellu- 
lose with  distilled  water,  for  some  time  in  an  open  vessel 
under  the  ordinary  pressure,  a  portion  of  it  is  converted 
into  sugar.  In  water  in  which  pure  filter-paper  has  been 
boiled,  the  presence  of  sugar  can  be  distinctly  established. 

The  action  of  water  upon  cellulose  is,  however,  consider- 
ably enhanced  by  boiling  for  a  certain  length  of  time  under 
increased  pressure.  With  a  pressure  of  5  to  6  atmospheres 
the  cellulose  is  very  noticeably  attacked,  and  the  higher 
the  pressure  becomes  the  more  energetically  the  water  acts 
upon  the  cellulose ;  with  a  pressure  of  20  atmospheres  the 
cellulose  becomes  completely  hydrated  and  is  changed  to 
hydrocellulose. 

However,  at  this  pressure  not  only  hydration  of  the  cellu- 
lose takes  place,  but  there  appear  also  other  products  re- 
sembling those  which  are  obtained  in  abundance  in  the 
destructive  distillation  of  wood,  especially  in  the  first  stages 
of  it ;  the  presence  of  considerable  quantities  of  formic  and 
acetic  acids  having  been  established  in  water  with  which 
cellulose  had  been  treated.  In  addition,  dextrin-like  bodies 
are  also  formed. 

HYDROCELLULOSE. 

The  combination  of  cellulose  with  water,  called  hydro- 
cellulose,  has  the  composition  C^  2H2  2Oi  i-  Hence  it  differs 
from  ordinary  cellulose  which  has  the  composition 
Ci2H20010  in  containing  one  more  equivalent  of  water. 
For  the  preparation  of  pure  hydrocellulose  use  is  made  of 
the  energetic  action  of  highly  dilute  acids  upon  cellulose 
even  when  brought  in  contact  with  them  at  a  lower  tem- 
perature. On  a  large  scale  the  mode  of  manufacture  is  as 
follows :  Mix  3  parts  of  concentrated  sulphuric  or  hydro- 


10         CELLULOSE,  AND  CELLULOSE  PRODUCTS. 

chloric  acid  with  97  parts  of  water,  and  immerse  in  the 
fluid  purified  cotton — entirely  free  from  fat — until  it  is 
completely  saturated,  which  will  be  the  case  in  at  the 
utmost  three  to  four  minutes.  The  cotton  is  then  taken 
from  the  mixture  and  freed  as  quickly  as  possible  from 
adhering  fluid,  this  being  best  effected  by  means  of  a 
centrifugal  apparatus.  It  is  then  spread  out  in  a  thin  layer 
and  allowed  to  dry  completely  in  the  air.  The  air-dry 
mass  is  finally  placed  in  stoneware  vessels  and  heated  for 
three  to  ten  hours  at  a  temperature  which  should  not  be 
below  104°  F.,  and  not  exceed  158°  F.;  the  higher  the 
temperature  the  less  time  is  required  for  heating.  The 
hydrocellulose  is  then  washed  with  water  till  the  last  traces 
of  acid  have  been  removed,  and  is  finally  completely  dried 
in  the  air. 

Hydrocellulose  has  the  appearance  of  the  cotton  from 
which  it  has  been  prepared,  but  can  be  readily  rubbed  to  a 
very  fine  powder.  It  is  manufactured  on  a  large  scale  be- 
cause it  possesses  the  property,  when  converted  into  gun- 
cotton,  of  yielding  a  product  which  can  be  more  readily 
exploded  by  percussion  than  ordinary  gun-cotton,  and  it  is, 
therefore,  preferably  used  for  the  preparation  of  detonating 
fuses  for  military  purposes. 

For  the  preparation  of  larger  quantities  of  hydrocellulose, 
R.  Sthamer  uses  the  following  process :  Chlorine  is  con- 
ducted into  glacial  acetic  acid  until  the  latter  is  perceptibly 
colored  yellow.  It  is  then  heated  to  between  140°  and 
158°  F.,  and  dry  cellulose  separated  into  fibres  is  intro- 
duced while  the  mass  is  constantly  stirred.  The  cellulose 
in  a  short  time  swells  up  very  much,  so  that  the  mass  can 
scarcely  be  stirred,  hence  three  to  five  parts  by  weight  of 
acetic  acid  should  be  used  to  one  part  by  weight  of  cellu- 
lose. The  mass  at  first  increases  constantly  in  volume,  but 
after  some  time  it  sinks  down,  and  is  finally  transformed 
into  a  thin  paste  which  is  washed  with  water  and  dried. 
Care  must  be  taken  not  to  allow  the  temperature  to  rise 


CELLULOSE.  11 

above  158°  F.,  as  otherwise  oxidizing  processes  may  take 
place  in  the  mass,  and  the  hydrocellulose  would  not 
exhibit  a  pure  white,  but  a  brownish  color. 

In  place  of  glacial  acetic  acid,  hydrochloric  acid,  which 
is  cheaper,  may  also  be  used  for  the  preparation  of  hydro- 
cellulose,  the  process,  according  to  Sthamer  being  as  fol- 
lows :  Bring  into  a  vessel  provided  with  a  steam  jacket  and 
a  stirring  apparatus,  200  Ibs.  of  cellulose  in  fibres  and  add, 
with  constant  stirring,  1600  to  2000  Ibs.  of  crude  hydro- 
chloric acid  of  21°  Be'.,  keeping  the  temperature  at  158°  F. 
A  small  quantity  of  finely  pulverized  potassium  chlorate — 
about  0.5  to  0.8  oz.  at  a  time — is  from  time  to  time  added 
to  the  mass.  When  in  the  course  of  about  1 J  hours  a  total 
quantity  of  2  Ibs.  of  potassium  chlorate  has  been  added, 
the  formation  of  hydrocellulose  may  be  considered  finished, 
the  end  of  the  reaction  being  recognized  by  the  uniformly 
pasty  nature  of  the  mass.  The  hydrochloric  acid  is  whirled 
out  by  means  of  a  centrifugal  apparatus,  and  may  be  used 
for  the  next  operation.  The  hydrocellulose  is  then  washed 
and  dried.  The  time  required  for  finishing  the  process  de- 
pends largely  on  the  nature  of  the  cellulose  used,  a  fine- 
fibered  material  requiring  less  time  than  one  with  close 
and  tough  fibres. 

Hydrocellulose  prepared  with  the  use  of  potassium 
chlorate  is  said  to  be  distinguished  by  very  great  chemical 
indifference  towards  acids  and  lyes,  and  its  use  for  the 
manufacture  of  articles  which  come  in  contact  with  them  is 
especially  recommended  by  Sthamer. 

BEHAVIOR  OF  CELLULOSE  TOWARDS  ACIDS. 

While  in  the  presence  of  even  small  quantities  of  acid, 
especially  of  strong  inorganic  acids,  the  action  of  water 
upon  cellulose  is  very  much  enhanced,  the  acids  them- 
selves do  not  enter  into  combination  with  the  products 
formed.  Hence  it  may  be  supposed  that  by  the  action  of 
the  acids  upon  the  cellulose  certain  combinations  are 


12  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

formed  which,  however,  are  again  immediately  decomposed 
so  that  the  liberated  acid  can  act  upon  a  fresh  quantity  of 
cellulose.  If  this  supposition  is  correct,  the  phenomenon 
of  the  mere  presence  of  minute  quantities  of  acid  being 
sufficient  to  change  an  almost  unlimited  quantity  of  cellu- 
lose is  readily  explained. 

The  behavior  of  cellulose  towards  acids  varies  according 
to  the  kind  of  acid,  its  concentration,  and  duration  of  its 
action.  Highly  diluted  sulphuric  acid  has  no  effect  what- 
ever, even  if  left  for  a  long  time  in  contact  with  cellulose, 
but  when  boiled  with  it  for  some  time,  the  cellulose  is 
partly  transformed  into  fermentable  sugar.  Upon  this  be- 
havior are  based  various  processes  for  the  preparation  of 
alcohol  from  cellulose  or  wood.  The  fluid  obtained  by 
boiling  cellulose  with  dilute  sulphuric  acid  is  neutralized 
with  lime  and  brought  into  alcoholic  fermentation  with 
yeast.  The  process  has  the  appearance  of  being  a  very 
simple  and  obvious  method  of  manufacturing  alcohol,  nev- 
ertheless in  practice  a  number  of  difficulties  are  encoun- 
tered, so  that  hitherto  very  little  use  has  been  made  of  this 
property  of  cellulose. 

When  cellulose,  best  in  the  form  of  unsized  paper,  is  for 
a  few  seconds  immersed  in  concentrated  sulphuric  acid,  and 
the  acid  is  then  quickly  removed  by  washing  in  a  large 
quantity  of  water,  it  undergoes  a  profound  physical  change. 
The  paper  by  this  treatment  acquires  great  strength,  and  in 
appearance  resembles  parchment.  By  treating  paper  with 
concentrated  solution  of  zinc  chloride,  a  product  resembling 
parchment  is  also  obtained. 

Cellulose  is  completely  dissolved  if  allowed  to  remain 
for  some  time  in  contact  with  cold  concentrated  sulphuric 
acid.  If,  in  a  short  time  after  solution  is  complete,  the 
fluid  be  diluted  with  water,  a  colorless  body  having  the 
composition  of  cellulose  is  separated  and  which,  from  its 
resemblance  to  starch,  has  been  termed  amyloid. 

If  solution  of  cellulose  in  concentrated  sulphuric  acid  be 


CELLULOSE.  13 

allowed  to  stand  for  some  time,  the  cellulose  is  completely 
converted  into  dextrin. 

However,  when  boiled  with  concentrated  sulphuric  acid, 
cellulose  is  entirely  decomposed,  and  by  reason  of  its  car- 
bonization imparts  to  the  fluid  a  deep  black  color.  The 
sulphuric  acid  is  also  decomposed,  as  shown  by  the  develop- 
ment of  sulphur  dioxide  from  the  hot  fluid. 

Generally  speaking,  the  action  of  hydrochloric  acid  upon 
cellulose  is  similar  to  that  of  sulphuric  acid,  its  effect,  how- 
ever, being  less  energetic,  and  in  boiling  cellulose  with  it 
no  carbonization  takes  place. 

Sulphurous  acid  acts  quite  energeticalty,  especially  with 
the  use  of  higher  pressure,  and  converts  cellulose  partially 
into  fermentable  sugar. 

By  organic  acids,  such  as  tartaric,  citric  and  acetic  acids, 
cellulose  is  but  slightly  attacked,  they  acting  somewhat 
more  energetically  when  in  a  concentrated  state;  oxalic 
acid  produces  the  most  vigorous  effect. 

Nitric  acid  effects  profound  chemical  changes  in  cellulose, 
the  nature  of  the  products  formed  depending  on  the  con- 
centration of  the  acid  used  and  the  duration  of  its  action. 
Cellulose  esters  or  cellulose  nitrates  or  nitro-cellulose  are 
formed,  a  group  of  combinations  which  are  especially  dis- 
tinguished by  their  power  of  exploding  with  great  force 
and  dissolving  in  various  bodies.  However,  notwithstand- 
ing the  profound  chemical  change,  nitrated  cellulose  ex- 
hibits no  difference  in  its  physical  structure.  Under  the 
microscope  it  presents  the  same  appearance  as  non-nitrated 
cotton,  but  differs  from  it  essentially  in  its  behavior  towards 
polarized  light. 

The  acid  sulphites  of  the  alkalies  and  alkaline  earths 
attack  cellulose  only  to  a  very  limited  extent,  but  they  act 
all  the  more  vigorously  upon  the  encrusting  substance  of 
the  wood.  The  same  is  the  case  with  free  chlorine,  and 
the  action  of  the  sulphites  and  of  chlorine  (the  latter  in  the 
electro-chemical  process)  is  made  use  of  in  the  preparation 
of  cellulose  from  wood. 


14  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

Cellulose  also  forms  with  a  number  of  organic  acids,  such 
as  acetic  acid,  butyric  acid,  etc.,  combinations  which  possess 
the  characters  of  esters.  These  combinations,  which  have 
only  recently  been  discovered  and  investigated,  show  prop- 
erties which  lead  to  the  expectation  that  they  may  also  be 
of  industrial  importance,  though  at  present  they  only  have 
been  experimented  with  on  a  small  scale. 

BEHAVIOR    OF    CELLULOSE    TOWARDS    ALKALIES. 

The  caustic  alkalies — caustic  potash  and  caustic  soda — 
when  allowed  to  act  for  a  short  time  produce  a  favorable 
change  in  cellulose,  the  fibres  becoming  more  compact  and 
solid,  so  that  fibres,  especially  those  of  cotton  thus  treated, 
can  be  more  readily  dyed  and  acquire  a  more  beautiful 
color  than  the  ordinary  material. 

When  concentrated  solutions  of  caustic  alkali — caustic 
potash  or  caustic  soda — are  for  a  short  time  allowed  to  act 
upon  cellulose  (cotton)  the  fibres  undergo  a  peculiar  change. 
Fibres  thus  treated,  when  viewed  under  the  microscope, 
appear  very  much  swollen,  their  cross  sections  are  much 
enlarged  and  nearly  circular,  and  the  cavity  in  the  interior 
is  so  much  smaller  that  it  can  scarcely  be  recognized  ;  the 
twist  of  the  fibre  is  also  considerably  increased. 

By  this  treatment  the  fibres  become  also  more  solid  and 
firmer  and  in  dyeing  behave  differently  from  ordinary  ma- 
terials. With  the  use  of  the  same  dyeing  liquor  they  ac- 
quire a  much  fuller  tone  of  color,  and  the  same  result  is 
obtained  with  smaller  quantities  of  coloring  matter  than 
otherwise  would  be  possible. 

This  peculiar  behavior  of  the  cotton  fibre  was  discovered 
by  John  Mercer  and  introduced  by  him  in  the  practice  of 
cotton  dyeing.  The  term  mercerization  has  been  applied  to 
the  process,  and  it  is  much  used  at  the  present  time. 

By  treating  cellulose  with  highly-concentrated  solution  of 
caustic  alkalies  it  is  largely  converted  into  oxalic  acid. 

By  treating  cellulose  with  a  suitable  quantity  of  caustic 


CELLULOSE.  15 

soda  and  then  adding  to  the  mass  a  certain  quantity  of  car- 
bon disulphide,  a  thickly-fluid  solution  is  obtained  which  is 
distinguished  by  an  extraordinary  adhesive  power.  By 
heating,  the  solution  is  again  decomposed,  whereby  the  car- 
bon disulphide  is  volatilized  and  the  cellulose  passes  again 
into  an  insoluble  form. 

BEHAVIOR    OF    CELLULOSE    AT    AN   INCREASED    TEMPERATURE. 

Cellulose  exposed  in  a  close  vessel  to  a  higher  tempera- 
ture commences  to  decompose  at  about  302°  F.,  and  when 
the  temperature  is  constantly  increased  there  remains  fin- 
ally a  lustrous  black  coal.  By  this  heating,  or  destructive 
distillation  as  it  is  called,  various  products,  partially  gase- 
ous, partially  fluid  or  solid,  are  formed.  The  gaseous  pro- 
ducts form  to  upwards  of  30  per  cent,  of  the  weight  of  the 
cellulose,  and  consist  chiefly  of  varying  quantities  of  car- 
bonic acid  and  carbonic  oxide.  The  fluid  products  separate 
in  two  layers,  one  of  them  being  of  an  aqueous  nature  and 
amounting  to  about  40  per  cent,  of  the  weight  of  the  cellu- 
lose, while  the  other  represents  a  thick,  viscous  mass — the 
so-called  wood  tar — of  a  dark  brown,  nearly  black,  color, 
which  amounts  to  from  4  to  6  per  cent,  of  the  weight  of  the 
cellulose. 

The  aqueous  fluid,  the  so-called  wood  vinegar,  contains, 
besides  water,  considerable  quantities  of  acetic  acid,  acetone, 
methyl  alcohol,  small  quantities  of  butyric  acid  and  other 
combinations.  The  wood  tar  consists  of  a  large  series  of 
hydrocarbons  which  are  partially  fluid  or  of  an  oil-like 
nature,  while  other  constituents,  to  which  belongs  paraffine, 
are  at  the  ordinary  temperature  solid  and  crystalline. 

It  will  be  seen  from  the  brief  explanations  given  above 
of  the  behavior  of  cellulose  towards  the  action  of  chemicals 
and  of  the  effect  of  higher  temperatures  upon  it,  that  it 
forms  the  basis-material  of  a  large  series  of  combinations  of 
great  technical  importance.  In  the  forms  in  which  it  is 
yielded  by  the  so-called  textile  plants,  it  constitutes  the 


16  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

chief  material  of  the  textile  industry  and  partially  supplies 
the  material  for  the  manufacture  of  paper,  though  for  the 
latter  purpose  the  artificial  product  furnishes  an  exceed- 
ingly valuable  substitute.  Cellulose  is  further  used  in  the 
manufacture  of  most  of  the  blasting  materials  and  explosive 
bodies,  for  the  preparation  of  viscose,  celluloid  and  several 
other  substances,  and  it  may,  therefore,  be  properly  called 
one  of  the  most  important  raw  materials  of  the  textile  and 
chemical  industries. 

INDUSTRIAL    USES    OP    CELLULOSE. 

Cellulose  and  its  derivatives  are  used  for  many  purposes, 
and  the  object  of  the  enumeration  here  given  is  simply  to 
show  in  a  comprehensive  manner  the  great  importance  of 
these  bodies  for  the  various  industries. 

Pure  cellulose  as  at  present  prepared  from  wood  is  most 
extensively  employed  in  the  manufacture  of  paper  and  con- 
siderable quantities  of  it  are  also  used  for  the  manufacture 
of  fire-proof  paste-board  for  roofing  (carton  pierre),  for  the 
preparation  of  plastic  masses,  and  as  an  excellent  filter 
material. 

The  term  vegetable  parchment  has  been  applied  to  cellulose 
in  the  form  of  paper  which  has  been  changed  by  subjecting 
it  for  a  short  time  to  the  action  of  concentrated  sulphuric 
acid.  On  account  of  its  strength  it  is  used  for  book  bind- 
ings, as  well  as  a  dialyzer  in  various  chemical  industries, 
for  instance,  in  the  manufacture  of  sugar. 

Cellulose  sulphocarbonate  or  viscose  is  used  as  a  sizing 
material  for  dressing  tissues,  as  a  thickening  substance  in 
calico-printing  and  for  the  preparation  of  textile  threads. 
In  the  course  of  time,  it  very  likely  will  also  be  applied  to 
other  purposes.  Solutions  of  pure  cellulose  in  cuprammon- 
ium  are  at  present  used  in  a  similar  manner  to  viscose  for 
the  production  of  textile  threads. 

To  the  important  derivatives  of  cellulose  belong  the  com- 
binations to  which  the  general  term  of  nitrocelluloses  has 


CELLULOSE.  17 

been  applied.  Some  of  these  combinations  are  distin- 
guished by  great  explosive  power  and  are  extensively  used 
for  the  preparation  of  blasting  agents,  while  others,  which 
are  soluble  in  certain  fluids,  form  with  them  the  so-called 
collodion  which  is  used  in  surgery  and  photography  and, 
in  modern  times,  also  for  the  preparation  of  textile  threads 
to  which  the  term  artificial  silk  has  been  applied. 

The  peculiar  substance  formed  by  bringing  together 
nitrocellulose  with  certain  hydrocarbons  and  known  as 
celluloid  has  found  many  applications  in  the  industries  and 
arts. 

The  general  suggestions  which  have  here  been  made  as 
to  the  utilization  of  cellulose  and  its  derivatives  suffice  to 
prove  that  they  belong  to  the  most  important  bodies  avail- 
able to  the  industries. 

The  conversion  of  cellulose  into  fermentable  sugar,  and 
of  the  latter  into  alcohol,  being  actually  possible,  it  is  not 
unlikely  that  some  time  or  another  in  the  future  a  process 
will  be  perfected  by  means  of  which  the  production  of 
alcohol  from  cellulose,  relatively  wood,  will  be  more 
profitable  than  from  plants  containing  starch.  Since  alco- 
hol itself  forms  the  initial  material  for  the  preparation  of 
many  other  chemical  products,  such  as  ether,  vinegar,  etc., 
a  new  field  for  the  utilization  of  cellulose  would  be  opened 
and  the  import  of  the  invention  of  a  suitable  process  for 
the  production  of  alcohol  from  wood  can  scarcely  be  esti- 
mated. Present  experiences  in  this  line,  though  encour- 
aging, are  not  sufficiently  perfected  for  their  application  on 
a  large  scale.  However,  it  may  be  fairly  asserted  that  the 
rational  preparation  of  alcohol  from  wood  is  only  a  ques- 
tion of  time. 

PRODUCTION  OF  CELLULOSE. 

Up  to  modern   times — about   the   first  half  of  the   nine- 
teenth century — no  other  sources  for  cellulose  than  certain 
parts  of  plants  were  known,      hi   warmer  countries  where 
2 


18  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

the  cotton  plant  thrives,  the  hair  which  grows  around  the 
seed  and  which  consists  almost  of  pure  cellulose,  formed  the 
material  for  the  preparation  of  textile  threads.  In  coun- 
tries having  a  colder  climate,  flax,  as  well  as  hemp,  has 
from  time  immemorial  been  the  principal  source  of  cellu- 
lose fibres. 

In  addition  to  the  plants  mentioned  above,  a  number  of 
others  were  to  a  more  limited  extent  utilized  in  other  parts 
of  the  globe  for  the  production  of  cellulose.  However,  the 
use  of  such  plants  was  merely  local,  while  that  of  cotton, 
flax  and  hemp  was  universal. 

Since  communication  with  cotton-producing  countries 
has  been  greatly  facilitated,  this  material  has  been  gen- 
erally adopted  in  Europe  and  has  in  many  cases  displaced 
flax  for  the  production  of  textile  fibres. 

Paper  consists  of  cellulose  fibres  felted  together  in  a 
peculiar  manner,  and  formerly  linen  rags  were  exclusively 
used  for  its  manufacture.  In  consequence  of  the  enormous 
increase  in  the  consumption  of  paper  the  price  of  rags  ad- 
vanced constantly,  and  it  became  necessary  for  the  paper 
manufacturer  to  find  other  sources  of  cellulose  suitable  for 
his  purposes. 

It  had  for  a  long  time  been  known  that  unlimited 
quantities  of  cellulose  were  available  in  the  higher  plants, 
the  larger  part  of  their  tissues  consisting  of  it.  However, 
this  cellulose  occurs  in  such  a  form  that  no  means  were 
known  by  which  it  could  be  separated  in  a  suitable  shape 
for  the  manufacture  of  paper. 

The  first  experiments  made  in  this  direction  were  for  the 
purpose  of  obtaining  the  cellulose  contained  in  the  straw  of 
the  various  kinds  of  grain.  The  results  of  these  experi- 
ments were,  however,  satisfactory  only  in  so  far  that  a 
material  was  obtained  which  ai  the  best  was  only  suitable 
as  an  addition  to  the  cellulose  mass  prepared  from  rags. 
When  used  by  itself  for  the  manufacture  of  paper,  the  re- 
sulting product  was  of  a  very  inferior  quality  as  to  appear- 


CELLULOSE.  19 

ance  and  solidity.  A  substance  suitable  for  the  manufacture 
of  paper  was  obtained  from  maize  straw  and  yielded  some- 
what better  results,  Alois  Auer,  formerly  director  of  the 
Austrian  government  printing-office  at  Vienna,  deserving 
special  credit  for  his  efforts  in  this  respect. 

As  might  be  expected,  many  experiments  were  made  for 
the  purpose  of  obtaining  the  cellulose  contained  in  wood, 
but  none  of  them  was  successful  because  no  means  were 
known  to  bring  into  solution  the  encrusting  substance  by 
which  the  individual  vascular  bundles  are  cemented 
together. 

However,  the  production  from  wood  of  a  material  which 
would  at  least  serve  as  a  partial  substitute  for  cellulose,  in 
the  manufacture  of  paper  was  finally  successfully  accom- 
plished, though  the  paper  made  from  it  was  inferior  in 
quality  to  the  product  from  pure  cellulose. 

This  substitute  consisted  of  wood  reduced  to  a  more  or 
less  fine  condition  by  mechanical  means.  The  reduction 
was  effected  by  means  of  grindstones,  and  large  works  for 
the  manufacture  of  this  material  were  established.  How- 
ever, this  wood  pulp  prepared  by  mechanical  processes  was 
nothing  but  wood,  and  could  only  be  mixed  in  certain  pro- 
portions with  the  pulp  prepared  from  rags,  and  the  result- 
ing paper  was  of  an  inferior  quality.  It  was  brittle  and  its 
color  was  riot  pure,  and  by  exposure  to  light  soon  turned 
brownish.  It  constituted,  however,  a  valuable  material  for 
newspapers  and  other  printed  matter  intended  for  tem- 
porary purposes.  In  the  manufacture  of  paper,  wood-pulp 
prepared  by  mechanical  means  is  at  present  only  used  for 
very  ordinary  grades ;  it  is,  however,  extensively  used  in 
the  manufacture  of  paste-board. 

By  the  efforts  of  chemists  a  process  was  finally  found  by 
means  of  which  it  was  rendered  possible  to  prepare  from 
wood  pure  cellulose  of  such  a  quality  as  to  be  suitable  for 
the  better  grades  of  paper,  and  from  this  period  on  dates  a 
great  revolution  in  the  manufacture  of  paper. 


20  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

A  process  was  discovered  by  which  the  complete  solution 
and  destruction  of  the  lignin  or  encrusting  substance  of  the 
wood  is  made  possible,  so  that  the  individual  vascular 
bundles  are  deprived  of  their  coherence  arid  fall  apart,  and 
after  removing  the  solvent  and  bleaching,  appear  as  pure 
cellulose. 

Thus  far  only  two  groups  of  bodies  are  known  which 
may  be  used  for  the  destruction  of  the  encrusting  substance, 
namely,  the  caustic  alkalies,  alkaline  sulphites,  and  chlorine, 
and  one  or  the  other  group  of  these  combinations  is  em- 
ployed in  every  process,  no  matter  under  what  name  it 
may  be  known,  for  the  preparation  of  cellulose. 

To  judge  from  the  present  state  of  the  industry,  the  ques- 
tion as  regards  the  preparation  from  wood  of  cellulose  suit- 
able for  the  manufacture  of  paper  would,  therefore,  appear 
to  be  solved.  However,  there  remains  the  solution  of  a  no 
less  important  problem,  namely,  the  production  from  wood 
of  cellulose  of  such  a  quality  as  to  render  it  suitable  for  the 
preparation  of  textile  threads.  Many  experiments  have 
been  made  in  this  direction,  but  without  entirely  satis- 
factory results,  it  having  thus  far  been  only  possible  to 
make  cellulose  threads  a  few  millimeters  long,  while  fibres 
of  considerably  greater  length  are  required  for  textile 
purposes. 

There  can  scarcely  be  any  doubt  that  this  question  will 
also  be  solved  in  the  course  of  time,  and  we  will  then  have 
in  wood-cellulose  a  material  available  for  the  manufacture 
of  paper,  as  well  as  for  weaving  tissues,  and  which  will  to  a 
considerable  extent  be  detrimental  to  the  cultivation  ot 
cotton  and  flax. 

With  reference  to  what  has  been  said  above,  two  phases 
of  the  historical  development  of  the  production  of  cellulose 
from  wood  will  have  to  be  kept  in  view,  the  one  in  which 
the  efforts  were  directed  towards  the  preparation  by 
mechanical  processes  of  a  material  suitable  for  the  manu- 
facture of  paper,  and  the  other,  in  which  the  efforts  led  to 


CELLULOSE.  21 

the  production  of  pure  cellulose  from  wood.  According  to 
the  nature  of  the  chemicals  used,  the  manufacture  of  cellu- 
lose may  be  divided  into  that  of  soda-cellulose,  sulphite- 
cellulose  and  electro-chemical-cellulose. 

As  has  been  previously  mentioned,  the  problem  of  pro- 
ducing textile  threads  from  wood  has  thus  far  not  been 
satisfactorily  solved,  though  such  threads  are  at  the  present 
time  made  in  a  roundabout  way  from  cellulose.  As  this 
subject  will  be  fully  discussed  later  on,  it  need  here  be  only 
briefly  referred  to.  From  wood,  pure  cellulose  can  only  be 
obtained  in  the  form  of  short  fibres,  but  fluids  are  known 
in  which  the  cellulose  dissolves  without  undergoing  a 
change  as  regards  its  physical  and  chemical  properties. 
These  solutions  can  be  converted  into  very  long  and  ex- 
tremely thin  threads,  from  which  the  cellulose  can  be  sep- 
arated so  that  it  retains  all  its  original  properties.  Threads 
thus  produced  may  be  spun  into  yarn  like  other  textile 
fibres  and  from  such  yarn  fabrics  can  be  made  which  do 
not  differ  from  other  cellulose  tissues,  except  that  they 
present  a  more  beautiful  appearance  as  regards  smoothness 
and  lustre.  It  will  thus  be  seen  that,  even  at  the  present 
time,  cellulose  from  wood  may  actually  be  obtained — 
though  in  an  indirect  way — in  the  form  of  textile  fibres. 


II. 

WOOD-STUFF,  OR  MECHANICAL  WOOD-PULP. 

THE  term  wood-stuff  or  mechanical  wood-pulp,  is  applied 
to  wood  converted  by  purely  mechanical  means  into  a  fine- 
fibred  mass,  which  by  itself  may  serve  for  the  production 
of  coarser  grades  of  paste-board,  as  well  as  for  the  manu- 
facture of  various  articles.  Its  chief  use,  however,  is  as  an 
addition  to  paper  stock  for  the  manufacture  of  inferior 
grades  of  paper.  Although  wood-stuff,  if  properly  pre- 
pared, is  sufficiently  fine-fibred  to  be  made  into  paper  in 
the  paper  machine,  it  is  not  used  by  itself  for  this  purpose, 
because  such  paper  possesses  the  disagreeable  property  of 
becoming  darker,  and  acquiring  in  a  short  time  a  brown 
coloration  when  stored  exposed  to  the  light.  The  cause  of 
this  phenomenon  is  found  in  the  fact  that  the  wood-stuff 
still  contains  nearly  the  entire  quantity  of  encrusting  sub- 
stance, lignin,  etc.,  originally  present  in  the  wood,  these 
substances  being  subject  to  great  changes.  Hence,  in  the 
course  of  time  efforts  were  made  to  remove  these  substances 
from  the  wood,  so  that  only  pure  cellulose  remains  behind, 
which,  as  it  does  not  show  the  above-mentioned  defects,  can 
be  used  by  itself  for  the  manufacture  of  paper. 

The  process  of  grinding  wood  has  been  known  for  a  com- 
paratively long  time.  The  fundamental  idea  originated 
with  F.  G.  Keller,  of  Hainichen,  Saxony,  and  was  so  far 
perfected  by  him  in  conjunction  with  Heinrich  Voelter,  of 
Heidenheim,  Wurtemberg,  that  as  early  as  1846,  the  first 
patents  for  wood-grinding  processes  were  granted.  In  the 
second  half  of  the  19th  century,  wood-grinding  processes 
were  introduced  in  all  countries  abounding  in  varieties  of 

(22) 


WOOD-STUFF,  OR   MECHANICAL    WOOD-PULP.  23 

wood  suitable  for  the  purpose,  and  the  bulk  of  paste-board, 
as  well  as  that  of  ordinary  newspaper,  is  made  from  ground 
wood. 

Voelter's  process  of  wood  grinding  is  executed  as  follows  : 
Suitably  prepared  blocks  of  wood  are  pressed  against  a 
rapidly  revolving  grindstone  which  is  kept  constantly  wet 
by  water.  By  the  grindstone  the  wood  is  reduced  to  a 
mixture  of  fine  fibres,  larger  shreds,  quite  large  shavings, 
and  water.  This  mixture  is  first  caused  to  press  against  a 
quite  coarse  wire  screen  which  retains  the  coarser  shavings 
and  splinters.  From  this  screen  the  mass  is  led  through  a 
series  of  cylindrical  screens  covered  with  wire  gauze  increas- 
ing in  fineness,  so  that  from  the  last  screen  a  thin  paste 
consisting  of  the  finest  wood  fibre  and  water  runs  off.  The 
separation  of  the  wood  fibres  from  the  water  is  effected  in 
various  ways,  it  being  frequently  accomplished  by  allowing 
the  paste  to  flow  over  an  endless  fine-meshed  metallic  cloth. 
The  water  runs  off  through  the  meshes  while  the  fibres  in 
the  form  of  a  delicate  pulp  remain  upon  the  cloth,  and  may 
be  still  further  freed  from  water  by  rolls.  In  this  case,  the 
pulp  is  very  frequently  conducted  at  once  to  the  rolls  of  the 
paper  machine  where  it  is  converted  into  sheets  of  fixed 
size.  According  to  another  method,  the  pulp  is  allowed  to 
drain  off  in  large  boxes  and  is  then  freed  from  water  by 
pressing. 

WOOD    FOR    GRINDING. 

Although  every  kind  of  wood  may  be  ground,  the  differ- 
ent varieties  are  by  no  means  alike  suitable  for  the  pur- 
poses for  which  the  pulp  is  to  be  used.  Of  the  European 
varieties  of  wood,  asp,  linden,  fir,  pine  and  birch  are  espe- 
cially well  adapted  for  the  purpose,  while  beech  is  less 
suitable.  In  America  the  soft  white  wood  of  the  tulip  tree 
(Liriodendron  tulipifera)  commonly  called  poplar,  as  well  as 
the  wood  of  spruce  and  pine,  is  used  in  large  quantities  for 
mechanical  wood-pulp. 


24 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


The  soft  white  woods  of  the  asp  and  linden  yield  a  beauti- 
ful white  pulp,  which,  however,  does  not  act  to  advantage 
in  the  paper-stuff,  paper  prepared  with  such  pulp  turning 
out  soft  and  spongy.  The  pulp  from  pine  or  fir,  to  be  sure, 
is  not  quite  so  white,  but  can  be  worked  into  firm,  smooth 
paper. 

Before  being  subjected  to  the  grinding  process  the  wood 
must  be  carefully  examined  and  prepared.  Decayed  or 
rotten  wood  should  be  absolutely  rejected  since  the  resulting 
pulp  would  have  a  brownish  color,  and  when  allowed  to  lie 
for  some  time  in  a  moist  state  would  become  mouldy 
throughout.  Hence  only  sound,  clean  wood  should  be 
worked. 

PREPARATION  OF  THE  WOOD  TO  BE  GROUND. 

The  preparation  of  the  wood  for  the  grinding  process  is 
effected  by  means  of  special  machinery.  The  blocks  of 


FIG.  3. 


FIG.  4. 


wood  are  first  submitted  to  a  machine,  which  is  a  sort  of 
revolving  plane,  and  cuts  away  the  bark.     Such  a  machine 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP.  25 

is  shown  in  front  and  side  views  in  Figs.  3  and  4.  As  will 
be  seen  from  Fig.  3,  three  knives  are  fixed  to  the  rapidly 
revolving  drum.  By  conducting  the  blocks  of  wood  against 
these  knives,  the  bark  is  cut  away,  care  being  taken  to  see 
that  it  is  completely  removed,  otherwise  the  pulp  will  in- 
evitably show  dark  spots. 

Since  knotty  wood  cannot  be  properly  ground,  the  knots 


FIG.  5. 


have  to  be  removed,  various  kinds  of  machinery  being 
used  for  this  purpose.  A  machine  of  simple  construction 
is  shown  in  Fig.  5,  the  removal  of  the  knots  being  effected 
by  means  of  a  rapidly  revolving  auger.  Another  machine 
for  the  purpose,  Fig.  6,  is  furnished  with  a  spoon-shaped 


26 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


auger,  which  is  set  in  rapid  motion  by  the  bevel  gear,  Fig.  7. 
The  blocks  of  wood  thus  prepared  are  cut  by  means  of  a 
circular  saw  into  pieces  of  such  a  length  that  they  can  be 
laid  in  the  individual  pockets  of  the  grinding  apparatus. 
Each  block  is  finally  split  into  at  least  two  pieces  by  means 


FIG.  6. 


FIG.  7. 


ri 


I 


7 


of  a  splitting  machine,  Fig.  8.  The  chief  object  of  this 
splitting  is  not  so  much  to  chop  up  the  wood  as  to  give  an 
opportunity  for  examining  it  inside,  since  many  blocks  ap- 
pearing perfectly  sound  from  the  outside  may  be  rotten  at 
the  core,  and  hence  of  no  use  for  the  preparation  of  pulp. 

When  the  wood  has  been  thus  freed  from  bark  and  knots, 
and  on  splitting  been  found  to  be  sound  throughout,  it  is 
ready  for  the  grinding  machine. 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP. 


WOOD-GRINDING    MACHINES. 


27 


Every  kind  of  machine  for  grinding  wood  consists  of  a 
grindstone,  generally  of  fine-grained  sandstone,  which  re- 
volves with  great  velocity  around  its  axis,  and  against  the 
surface  of  which  the  wood  is  pressed,  the  latter  being  kept 
constantly  wet  with  water.  The  wood  is  placed  so  that  its 
vascular  bundles  lie  parallel  to  the  surface  of  the  grind- 
stone. The  latter  in  revolving  tears  from  the  wood  indi- 

FIG.  8. 


vidual  vascular  bundles,  as  well  as  entire  groups  of  them, 
and  not  seldom  even  larger  splinters.  The  mass  torn  loose 
is  carried  by  the  water  into  a  vat,  in  which  the  revolving 
stone  is  placed,  and  from  there  to  the  sorting  contrivances, 
by  which  the  different-sized  particles  of  wood  are  separated 
one  from  the  other. 


28  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

The  oldest  of  these  machines  is  that  constructed  by 
Voelter,  and  it  has  proved  so  satisfactory  that  up  to  the 
present  time  it  has  undergone  but  slight  modifications,  its 
main  features  remaining  the  same. 

In  Voelter's,  as  well  as  in  other  machines  built  in  imita- 
tion of  it,  the  grindstone  is  fixed  to  a  horizontal  shaft,  but 
in  some  more  modern  constructions,  to  a  vertical  shaft. 
However,  a  horizontal  position  of  the  shaft  is  considered 
more  suitable  by  all  who  have  had  the  opportunity  to  test 
the  capacity  of  the  different  machines. 

VOELTER'S  GRINDING  MACHINE. 

Voelter's  grinding  machine,  Fig.  9,  consists  of  a  frame 
having  two  strong,  cast-iron  sides  firmly  bolted  together  and 
supporting  the  bearings  of  the  grindstone.  One  side  of  the 
frame  is  so  arranged  that  the  sheet-iron  jacket  can  be  re- 
moved so  as  to  allow  of  the  grindstone  being  readily  ex- 
changed without  the  necessity  of  taking  the  entire  machine 
apart.  Between  the  two  sides,  fixed  to  their  surfaces,  are 
pockets  or  boxes,  in  which  the  wood  to  be  ground  is  placed. 
The  blocks  of  wood  are  pressed  against  the  grindstone  by  a 
spur  gearing,  uniform  pressure  being  kept  up  by  means 
of  a  tight  endless  chain.  The  arrangement  of  this  mechan- 
ism is  such  that  when  one  pocket  becomes  disengaged,  the 
others  receive  a  somewhat  stronger  pressure,  the  uniform 
running  of  the  machine  being  thus  constantly  maintained, 
and  one  or  two  pockets  may  be  refilled  without  stopping 
the  machine. 

The  grindstone  is  somewhat  wider  than  the  blocks  of 
wood  to  be  ground,  and  is  furnished  with  a  mechanical 
contrivance  by  means  of  which,  while  it  revolves,  it  can 
alternately  be  shifted  towards  the  right  and  the  left.  The 
effect  of  this  arrangement  is  that  not  only  the  stone  wears 
more  uniformly,  but  its  disintegrating  action  upon  the 
wood  is  also  increased.  The  pockets  in  which  the  wood  is 
placed  have  the  form  of  truncated  pyramids.  Each  pocket 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP. 


29 


is  provided  with  a"strong,  cast-iron  cover  which  is  pressed 
down  by  the  racks  connected  with  the  spur  wheels,  the 
latter  being  constantly  drawn  down  by  the  endless  chain. 
When  a  pocket  has  been  filled  with  wood,  the  cover  is 
placed  in  position  and,  by  engaging  the  spur  wheel,  is 
firmly  pressed  upon  the  wood,  and  the  latter  is  then  sub- 
mitted to  the  grinding  action  of  the  stone.  Each  pocket  is 

FIG.  9. 


furnished  with  a  pipe  through  which  an  abundance  of 
water  is  constantly  conducted  over  the  wood  and  the  stone. 
The  fragments  of  wood  detached  by  the  stone,  being  imme- 
diately washed  away,  fall  to  the  bottom  of  the  vat,  and  are 
carried  to  the  sorting  screens.  As  the  water  is  generally 
introduced  in  fine  jets  under  high  pressure,  the  detached 
particles  of  wood  are  sure  to  be  washed  away  by  the  force 


30 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


thus  brought  to  bear  upon  them,  and  there  is  no  danger  of 
the  machine  becoming  clogged  by  splinters. 

There  are  numerous  constructions  of  machines  in  which 
the  grindstones  are  placed  vertically,  but  in  principle  they 
do  not  differ  from  Voelter's  machine.  Some  of  them,  how- 
ever, show  certain  improvements  as  regards  the  mode  of 
pressing  the  blocks  of  wood  against  the  grindstone. 

FIG.  10. 


A.  Oser's  machine,  Fig.  10,  is  so  arranged  that  a  constant 
and  adjustable  pressure  upon  the  blocks  of  wood  by  the 
endless  chain  is  produced  by  means  of  a  movable  crank,  a, 
which  receives  its  impulse  from  the  shaft  of  the  stone, 
further  by  the  spring-connecting  rod,  b,  the  contrivance  for 
engaging  the  binding  attachment,  c,  and  the  connecting 
gear,  which  is  set  in  motion  by  the  wheels,  d  e  and  /  g. 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP. 


31 


Fig.    11    shows    Voith's  wood-grin  diner  machine,  which 
differs  but  little  from  the  one  described  above. 

FREITAG'S  GRINDING  MACHINE. 

This  is  an  original  construction  of  a  grinding  machine 
with  stones  fixed  to  a  perpendicular  shaft.     Four  or  five 

Fro.  11. 


grindstones,  each  having  a  diameter  of  only  about  20 
inches,  are  used,  and  their  bearings  are  so  arranged  that  the 
surfaces  of  all  the  stones  can  be  adjusted  at  exactly  the  same 
height.  The  wood  to  be  ground,  in  the  form  of  a  long 
block,  Fig.  12,  is  laid  upon  the  stones,  pressed  against  them 


32 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


by  means  of  an  iron  plate,  and,  during  the  process  of  grind- 
ing, is  to  a  fixed  extent  moved  to  and  fro.     This  grinding 


FIG.  12. 


i 


LJTJLJLJ 


FIG.  13. 


apparatus  is  said  to  furnish  especially  long  fibres  which  is 
certainly  of  great  advantage  for  the  quality  of  the  pulp. 

ABADIE'S  GRINDING  MACHINE. 

Of  an  entirely  different  construction  are  the  wood-grind- 
ing machines  in  which  one  of  the  circular  surfaces  of  the 

stone  is  used  as  the  grind- 
ing plane,  as  is  the  case  in 
the  machine  constructed 
by  August  Abadie.  This 
machine,  Figs.  13  and  14, 
is  furnished  with  four 
press-pockets,  A,  the  pis- 
tons of  which  are  loaded 
with  the  weights,  L  The 
load  may  be  increased  by 
the  use  of  the  connecting 
gears  fixed  above  k,  which 
serve  also  for  raising  the 
press-pockets  when  they 

are  to  be  refilled.  In  the  spaces  i  between  the  press-pockets, 
weights  of  iron,  stone  or  wood  are  to  be  placed,  their  object 
being  immediately  to  grind  up  the  wood-stuff  detached  by 
the  grindstone.  This  specification,  however,  has  yet  to  be 
proved  by  direct  experiments. 

It  is  a  matter  of  experience  that  the  wood -stuff  detached 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP. 


33 


Fio.  14. 


from  the  blocks  of  wood  in  one  press-pocket,  should  as 
rapidly  as  possible  be  withdrawn  from  the  further  action  of 
the  machine,  since  the  fibres,  when  dragged  again  into 
another  pocket  and  there  again  exposed  to  the  action  of  the 
grindstone,  are  too  much  reduced  or  what  is  technically 
called  dead-ground.  This  contingency  need  not  be  feared  in 
Abadie's  machine,  since  the  water  is  supplied  from  the 
centre  of  the  machine  so  that  it 
is  forced  outward  by  centrifugal 
force  and  immediately  carries 
away  all  the  particles  of  wood 
lying  in  its  course.  The  indi- 
vidual pockets  or  presses  are 
fixed  in  a  frame  g,  and  the 
latter  is  pressed  firmly  against 
the  grindstone  by  three  per- 
pendicular screws  /,  and  ac- 
curately centered  by  three 
horizontal  screws. 

In  addition  to  the  construc- 
tions above  described,  there  are 
a  few  other  wood -grinding 
machines  in  which  the  stone  is 
fixed  to  a  vertical  shaft,  so  that 
its  entire  surface  may  be  set 
with  press-pockets.  In  an  ap- 
paratus of  this  kind,  con- 
structed by  Liebrecht,  eight 
grinding  pockets  in  all  are 
used,  and  the  wood  is  pressed 
against  the  grindstone  by  hydraulic  pressure.  Such  a 
machine,  of  course,  can  in  the  same  time  work  up  a  larger 
quantity  of  wood  than  one  with  only  four  or  five  grinding 
pockets,  but  it  must  also  be  borne  in  mind  that  the  con- 
sumption of  power  is  correspondingly  greater  and  that  the 
grindstone  is  subject  to  much  greater  wear. 
3 


34  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

Regarding  the  use  of  hydraulic  pressure  for  pressing  the 
wood  against  the  grindstone,  Liebrecht's  construction  in 
this  respect  must  be  acknowledged  as  a  very  ingenious  one. 
However,  the  apparatus  becomes,  thereby,  more  expensive 
and  more  complicated,  two  factors  which  are  not  in  favor 
of  a  machine  on  which  heavy  demands  are  made. 

In  construction,  Voelter's  wood-grinding  machine  is 
more  simple  than  any  other  apparatus  for  the  same  pur- 
pose, and  the  unexpected  giving-away  of  any  important 
part  can  scarcely  happen ;  furthermore,  the  grindstone  can 
be  readily  removed  and  in  a  short  time  replaced  by  another 
one.  With  this  machine,  as  shown  by  practical  experience, 
operations  can  be  carried  on  for  a  long  time  without  having 
to  stop  work  for  more  extensive  repairs. 

WATER  USED  FOR  GRINDING. 

Regarding  the  water  which  during  the  grinding  opera- 
tion has  to  be  constantly  conducted  upon  the  grinding  sur- 
face, it  may  be  mentioned  that  it  should  be  perfectly  clear 
and  free  from  suspended  solid  bodies — especially  sand  or 
clay.  Such  bodies  would,  of  course,  adhere  to  the  pulp 
and  affect  its  purity,  this  being  especially  the  case  with  par- 
ticles of  clay  contained  in  the  water  used.  Pulp  from  a 
variety  of  wood  which  otherwise  would  yield  a  nearly  white 
product,  acquires  by  a  content  of  clay — according  to  the 
color  of  the  latter — a  yellow  or  gray  appearance. 

Hence,  when  in  the  locality  where  a  grinding  plant  is  to 
be  established,  perfectly  clear  water,  free  from  sand  or  clay, 
is  not  available,  it  would  seem  advisable  to  pass  the  water 
required  for  grinding  through  a  filter  which  retains  the 
suspended  solid  bodies.  In  order  to  economize,  in  this  case, 
with  filtered  water,  the  water  running  off  from  the  sorting 
screens  is  not  allowed  to  flow  away,  but  is  collected  in  a 
basin  and  pumped  into  a  reservoir  placed  at  a  higher  level, 
from  which  it  is  reconducted  to  the  grinding  apparatus. 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP.  35 

SORTING  THE  GROUND  MASS. 

The  operation  subsequent  to  the  grinding  process  consists 
in  separating  the  different-sized  particles  detached  by  the 
grindstone  from  the  blocks  of  wood.  The  general  terra 
sorters  is  applied  to  the  various  contrivances  used  for  the 
purpose. 

Before  commencing  the  actual  sorting  operation,  the  fluid 
coming  from  the  grinding  apparatus  is  passed  through  the 
so-called  splinter-catcher.  The  latter  consists  of  a  larger 
vessel  in  which  sits  a  cylinder  with  slit  sides,  or  covered 
with  a  wire  screen.  The  cylinder  revolves  slowly  around 
its  axis  and  frequently  is  also  kept  in  an  oscillating  motion. 
The  particles  of  wood,  which  are  small  enough  to  pass 
through  the  slits  or  meshes  of  the  cylinder,  are  carried, 
together  with  the  water,  to  the  sorters,  whilst  the  coarser 
splinters  collect  in  the  box  of  the  splinter-catcher,  to  be 
further  reduced  in  special  mills. 

The  sorters,  which  serve  for  sorting  the  wood-stuff,  re- 
semble in  the  main  other  appliances  used  for  similar  pur- 
poses. They  consist  either  of  a  series  of  sieves  of  gradually 
increasing  fineness  which  are  kept  in  a  shaking  motion,  or 
of  revolving  cylinders  covered  with  wire  sieves.  In  place 
of  revolving  cylinders,  hexagonal  prisms  covered  with  wire 
sieves  are  also  used. 

Voith's  shaking  sieves  are  shown  in  Figs.  15  and  16. 
The  sifting  frames  consist  of  sheet  iron,  the  ends  being 
turned  up.  Each  frame  rests  upon  four  steel  springs,  d — d, 
e — e  and  /— /,  and  is  connected  with  a  spring-connecting 
rod,  g  hi.  The  cranked  axle  lies  in  k  I,  its  crank-pins  being 
placed  one  against  the  other  at  an  angle  of  120°,  whereby, 
in  connection  with  the  fly-wheel,  a  quite  uniform  running 
of  the  machine  is  attained. 

The  sieves  are  kept  in  a  very  rapid  jerking  or  shaking 
motion — 400  to  500  motions  per  minute.  By  the  use  of 
springs,  as  applied  in  the  above-described  machine,  the 
otherwise  great  wear  and  tear  of  the  machine  is  reduced 


36 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


and  the  very  loud  noise  made  by  the  shaking  sieves  is  con- 
siderably modified. 

The  mode  of  operation  of  the  shaking  sieve  is  a  very 
simple  one :  The  mass,  consisting  of  particles  of  wood  and 
water  which  conies  from  the  splinter-catcher,  falls  upon  the 

FIG.  15. 


uppermost  sieve.  Water  and  all  particles  of  wood  smaller 
than  the  meshes  fall  through  the  sieve,  whilst  the  coarser 
particles  slide  down  over  it  and  collect  in  a  receptacle. 
The  same  process  is  repeated  in  the  succeeding  sieves,  and  a 
pulp  of  delicate  particles  of  wood  and  water  runs  finally 
from  the  lowest  and  finest-meshed  sieve  into  the  settling  vat. 

FIG.  16. 


fed. 


With  the  use  of  cylinder-sieves  the  same  process  -  takes 
place  in  a  revolving  cylinder,  in  which  the  mass  coming 
from  the  splinter-catcher  is  freed  from  the  coarser  particles, 
then  passes  to  the  succeeding  narrower-meshed  cylinder- 
sieve,  and  so  on.  Instead  of  arranging  three  or  more 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP.  37 

cylinder-sieves  one  after  the  other  the  sieves  may  also  be 
fixed  one  inside  the  other  so  that  they  revolve  towards  each 
other  in  opposite  directions,  the  second  revolving  in  an 
opposite  direction  to  the  first  outermost,  and  the  third  again 
in  the  same  direction  as  the  outermost. 

The  mass  coming  from  the  splinter- catcher  passes  into 
a  trough  into  which  the  outermost  sieve  dips,  and  being 
carried  along  by  it,  reaches  the  second  sieve,  and  from  this 
finally  the  innermost  one. 

The  particles  of  the  ground  wood  which  have  passed 
through  the  sieve  with  the  narrowest  meshes  are  considered 
of  sufficient  fineness  not  to  require  further  manipulation. 
Hence  this  pulp  is  directly  conducted  to  the  settling  vats, 
the  dehydrating  apparatus  or  the  board  machines. 

The  particles  of  wood  which  are  not  sufficiently  ground 
have  to  be  further  reduced,  the  simplest  manner  of  accom- 
plishing this  being  by  means  of  mill-stones  of  ordinary  con- 
struction. However,  special  mills  which  are  better  adapted 
for  this  purpose  have  also  been  constructed.  Such  a  mill, 
known  as  a  refiner,  is  shown  in  Figs.  17  and  18. 

This  mill  differs  from  the  ordinary  constructions  in  being 
furnished  with  two  stationary  millstones  placed  in  a  verti- 
cal position,  between  which  revolves  a  runner  dressed  on 
both  sides.  Since  this  stone  possesses  two  grinding  planes, 
the  same  performance  can  be  attained  with  one  stone  of 
small  diameter  as  with  much  larger  stones  in  an  ordinary 
mill.  In  the  illustrations,  A,  B,  C  represent  the  three  stones, 
the  middle  stone  B  being  fixed  by  means  of  a  box-screw  to 
the  shaft  D.  The  stones  A  and  C  sit  upon  the  carriage 
F  F,  and  are  firmly  fixed  to  it  by  the  screws  u  and  u.  Z  is 
a  jacket  enclosing  the  stones,  and  the  carriage  F  F,  together 
with  the  stones,  can  be  shifted  in  it.  The  shifting  of  the 
stones  for  the  purpose  of  regulating  the  distance  between 
them  is  effected  by  means  of  the  wheel  J.  Both  stones  are 
simultaneously  shifted  upon  the  support  Z,  the  shaft  H 
being  furnished  with  a  left  and  right  thread.  S  represents 


38 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


the  contrivance  for  the  introduction  of  the  wood.  It  is 
fixed  to  the  jacket  Z  by  means  of  the  iron  supports  r  r,  and 
terminates  in  two  outlets  it.  S  is  a  gutter  also  furnished 
with  two  outlets,  so  that  the  wood  to  be  ground  reaches  the 
grinding  surface  by  means  of  t  I,  the  channels  W  W,  and 
the  two  exterior  sides  of  the  stones,  the  latter  receiving  it 
only  upon  the  lower  halves  of  their  circumferences.  The 
wood  remains  between  the  stones  only  long  enough  to  be 

FIG.  17. 


reduced  to  a  degree  of  fineness  corresponding  to  the  distance 
between  the  stones,  when  it  falls  down  on  its  own  account. 
In  place  of  the  refiner,  finely  corrugated  rolls  may  be 
used  for  the  reduction  of  the  particles  of  wood.  They  re- 
volve with  different  velocities  whereby  the  wood  is  at  the 
same  time  torn  and  crushed.  The  wood  thus  reduced  is, 
for  the  sake  of  precaution,  passed  through  a  fine-meshed 
sieve  in  order  to  retain  coarser  particles  which  may  have 
escaped  the  action  of  the  mill,  and  finally  reaches  the  con- 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP. 


39 


trivances  for  the  separation  of  the  pulp  from  the  water. 
These  contrivances  consist  of  revolving  cylinders  covered 
with  fine  gauze-wire  sieves  so  that  the  water,  but  not  the 
pulp,  can  pass  through.  By  this  means,  the  pulp,  to  be 
sure,  loses  considerable  water,  but  is  not  sufficiently  freed 
from  it,  the  use  of  special  apparatuses  being  required  for 

FIG.  18. 


the  complete  removal  of  the  water  as  far  as  it  is  at  all  pos- 
sible. 

The  water  running  off  from  the  dehydrating  cylinders 
always  carries  with  it  a  certain  quantity  of  the  finest  par- 
ticles of  the  pulp  which  is  sought  to  be  recovered  in  various 
ways,  sieves  of  the  finest  gauze  wire  being  most  frequently 


40  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

used  for  the  purpose.  The  water  flows  over  the  sieve  while 
the  air  is  exhausted  underneath  it.  The  water  penetrates 
through  the  meshes  while  the  pulp  remains  upon  the  sieve, 
and  is  removed  from  it  by  a  scraper. 

DEHYDRATION    OF    THE    PULP. 

The  removal  of  water,  as  far  as  possible,  from  the  pulp  is 
an  important  operation,  especially  if  the  pulp  is  to  be 
shipped,  because  the  smaller  the  content  of  water  the  less 
the  expense  for  freight  will  be.  If  the  pulp  is  to  be  used 
in  the  establishment  itself  in  which  it  is  prepared,  thorough 
dehydration  is  of  course  not  required,  it  being  only  necessary 
to  free  it  from  water  sufficiently  to  allow  of  the  preparation 
of  boards,  in  which  state  it  is  further  worked,  the  finished 
boards  being  finally  completely  dried. 

The  board  machine  consists  in  the  main  of  an  endless 
cloth  10  to  13  feet  long  which  is  stretched  tight  over  rolls 
so  as  to  present  a  perfectly  level  surface.  Over  this  cloth, 
several  wooden  rolls  lie  loose  in  crotches,  their  object 
being  to  distribute  uniformly  the  quite  thinly-fluid  pulp 
taken  up  by  the  endless  cloth  and,  at  the  same  time,  to 
somewhat  squeeze  it  out  by  their  weight.  By  this  means 
quite  a  tenacious  paste  is  obtained  on  the  portion  of  the 
endless  cloth  opposite  to  where  the  pulp  enters.  This  paste 
is  then  pressed  more  vigorously  between  two  iron  rolls  so 
that  it  forms  a  quite  firm,  coherent  mass.  This  is  allowed 
to  wind  several  times  round  a  roll  and  the  hollow  cylinder 
thus  formed  is  cut  through,  all  the  sheets  thus  produced 
being  of  the  same  size.  Sheets  of  any  desired  length  may 
also  be  formed  upon  an  endless  cloth  which  takes  up  the 
pulp.  If,  however,  in  place  of  sheets  thoroughly  dried,  or 
more  correctly,  thoroughly  dehydrated,  pulp  is  to  be  pro- 
duced, the  pulp  is  allowed  to  flow  over  a  cylinder  covered 
with  wire  cloth,  both  ends  of  which  are  rendered  as  tight  as 
possible  by  rubber,  and  under  which  vigorous  rarefaction 
of  air  is  maintained.  The  pulp  flowing  upon  the  slowly 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP.  41 

revolving  sieve  is  much  dehydrated  by  the  air-pressure  and 
is  removed  in  the  form  of  a  coherent  mass.  It  is  then 
again  vigorously  pressed  between  rolls  and  finally  divided 
by  smooth  rolls  into  small  pieces  which  are  immediately 
packed. 

If,  however,  the  pulp  is  to  be  freed  as  much  as  possible 
from  water  as  would  seem  necessary  for  transporting  it  long 
distances,  filter-presses  are  used,  a  quite  powerful  hydro- 
static pressure  being  produced  by  means  of  an  accumulator. 
In  the  chambers  of  the  press,  sheets  quite  dry  to  the  touch 
are  thus  obtained,  which  can  be  readily  packed  and  trans- 
ported long  distances.  The  only  drawback  as  regards  the 
use  of  filtering-presses  is  that  a  plant  working  on  a  larger 
scale  would  require  a  number  of  them  to  work  up  rapidly 
all  the  raw  material  furnished  by  the  grinding  machine. 

DRYING  APPARATUS. 

The  preparation  of  perfectly  dry  pulp  has  recently  been 
successfully  accomplished  without  too  large  an  expenditure, 
by  the  use  of  apparatus  which  in  its  construction  closely 
resembles  the  contrivances  employed  in  sugar  houses  and 
breweries  for  drying  beet  slices  and  grains.  They  are  so 
arranged  that  the  substance  to  be  dried  moves  in  a  direc- 
tion opposite  to  that  of  a  hot  air  current,  so  that  drying  is 
effected  by  a  counter-current.  The  substance  to  be  dried 
is  first  met  by  the  hot  air-current  while  it  still  contains  all 
the  water,  and  though  it  becomes  highly  heated,  it  loses 
but  little  water  by  evaporation,  the  latter  process,  however, 
proceeding  very  rapidly  as  the  heated  mass  advances. 

The  apparatuses  used  for  drying  pulp  are  generally  so 
arranged  that  the  crumbled  pulp  previously  freed  as  much 
as  possible  from  water  by  mechanical  means,  is  carried 
along  with  a  certain  velocity  upon  endless  wire  cloth,  while 
underneath  the  latter  a  hot  air-current  passes  in  an  opposite 
direction.  The  velocity  of  the  movement  of  the  pulp  upon 
the  cloth  is  fixed  by  the  temperature,  and  the  latter  has  to 


42  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

be  carefully  regulated.  By  the  use  of  such  an  apparatus 
the  pulp  may  be  only  partially  or  completely  dried,  as  may 
be  desired.  The  apparatus  is  furnished  with  automatic 
charging  and  discharging  contrivances. 

PROPERTIES  OF  WOOD-PULP. 

With  the  exception  of  pulp  completely  freed  from  water 
by  artificial  drying — and  this  exception  applies  only  to 
material  dried  shortly  after  its  preparation — its  color  under- 
goes a  considerable  change,  which,  of  course,  is  also  trans- 
mitted to  the  paper  prepared  from  it.  Experiments  made 
by  Cl.  Winkler  with  pulp  from  different  varieties  of  wood 
which  was  exposed  to  the  action  of  the  air  at  a  temperature 
of  between  30°  and  50°  F.,  gave  the  following  results: 

COLOR  OF  PULP. 

From  When  freshly  prepared  After  several  weeks. 

Pine  pale  yellow  pale  yellow 

Fir  yellow  yellow 

Scotch  fir  greenish-Avhite  dirty  reddish 

Larch  pale  yellow  pale  yellow 

Aspen  yellowish-white  yellowish- white 

Linden  gray-white  gray-white 

Maple  yellowish-white  yellowish-white 

Beech  pea  yellow  superficially  reddish 

Birch  yellowish-white  flesh  color 

Alder  deep  yellow  brick-red 

The  change  of  color  appears  first  upon  the  surface  of  the 
moist  pulp,  spreading  from  there  to  the  interior,  and  is, 
without  doubt,  a  process  of  oxidation.  Since  pure  cellulose 
does  not  exhibit  this  change  of  color,  it  can  only  be  caused 
by  a  chemical  change  of  the  lignin  and  eventually  of  the 
very  small  quantity  of  protein  substances.  The  content  of 
rosin  in  the  conifers  appears  to  exert  but  little  influence  as 
regards  the  change  of  color,  as  will  be  seen  from  the  be- 
havior of  the  pulp  prepared  from  them. 

The  change  in  color  of  the  pulp  being  very  annoying  as 
regards  the  paper  made  from  the  material,  experiments 


WOOD-STUFF,  OR    MECHANICAL   WOOD-PULP.  43 

have  been  made  to  overcome  this  defect  by  bleaching.  Of 
all  the-  bleaching  agents  experimented  with,  sulphurous 
acid,  produced  by  burning  sulphur,  is  the  only  one  which 
has  proved  of  value  in  practice.  The  simplest  mode  of 
application  is  to  conduct  sulphurous  acid  into  an  air-tight 
box  which  is  filled  with  broken  pulp  containing  60  per 
cent,  of  water.  The  gas  is  absorbed  with  avidity  by  the 
water,  and  the  entire  mass  is  in  a  short  time  saturated  with 
it.  Pulp  thus  bleached  should  not  be  allowed  to  lie  too 
long,  since  it  has  been  shown  that  after  some  time  it  con- 
tains sulphuric,  in  place  of  sulphurous,  acid.  When  the 
pulp  is  dried  in  the  air,  the  sulphuric  acid  acquires  a  cer- 
tain concentration  and  has  a  browning  effect  upon  the  pulp. 
Hence  the  bleached  mass  should  immediately  be  worked 
further. 

The  effect  of  the  sulphurous  acid  appears  to  be  that,  on 
the  one  hand,  it  arrests  the  oxidizing  action  of  the  air,  and, 
on  the  other,  that  it  enters  with  the  coloring  matter  con- 
tained in  the  pulp  into  a  colorless  combination,  which, 
however,  is  in  the  course  of  time  again  decomposed,  the 
sulphurous  acid  being  again  liberated  and  slowly  oxidized 
to  sulphuric  acid. 

PULP    FROM    STEAMED    WOOD. 

When  treated  with  water  under  high  pressure  and  at  a 
high  temperature  even  pure  cellulose  is  chemically  changed 
and  converted  into  hydrocellulose.  Wood,  when  treated  in 
a  similar  manner,  undergoes,  however,  more  far-reaching 
changes,  the  lignin  contained  in  it  being  very  likely  most 
effected,  because  by  the  treatment  with  high-pressure  steam 
the  fibres  are  considerably  loosened,  and  there  is  no  diffi- 
culty whatever  in  preparing  from  such  wood  a  pulp  which 
is  distinguished  by  particularly  long  fibres. 

The  quantities  of  substances  which  pass  into  solution  by 
steaming  vary  according  to  the  variety  of  wood.  In  steam- 
ing beech  26.75  per  cent,  passes  into  solution,  11.19  per 


44  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

cent,  of  this  being  sugar  and  substances  resembling  sugar. 
Steamed  pine  showed  a  loss  in  weignt  of  19.17  per  cent., 
9.07  per  cent,  of  this  being  sugar  and  substances  allied  to 
it.  The  latter  probably  consist  chiefly  of  dextrin-like 
bodies,  since  the  wood  extract  yields  with  alcohol  very 
heavy  precipitates. 

However,  in  addition  to  the  bodies  mentioned  above, 
there  are  formed  in  steaming  wood,  combinations  like  those 
appearing  in  abundance  at  the  commencement  of  the  de- 
structive distillation  of  wood.  In  water  in  which  wood  has 
been  steamed  are  found  considerable  quantities  of  acetic 
and  formic  acids.  When  resinous  woods  are  subjected  to 
steaming,  considerable  quantities  of  volatile  oil  escape  with 
the  aqueous  vapor  when  the  pressure  in  the  vessel  used  for 
steaming  is  interrupted. 

By  steaming  the  wood  acquires  a  more  or  less  dark 
leather  to  liver-brown  color,  and  the  fibres  are  very  much 
loosened.  By  reason  of  this  brown  coloration  of  the  wood, 
the  pulp  prepared  from  it  cannot  be  used  as  an  addition  in 
the  manufacture  of  white  paper.  It  is,  however,  very  suit- 
able for  the  production  of  stout  wrapping  paper,  because  it 
has  very  long  fibres,  which,  in  making  it  into  paper,  felt 
together,  the  resulting  product  being  very  durable  and 
flexible. 

In  its  construction  the  apparatus  used  for  steaming  wood 
resembles  a  cylindrical  steam  boiler,  both  upright  and  hori- 
zontal types  being  used.  It  is  advisable  to  line  the  walls 
of  iron  boilers  with  copper,  they  being  in  the  course  of 
time  strongly  attacked  by  the  organic  acids  formed  from 
the  wood. 

The  production  of  pulp  from  steamed  wood  may  be 
effected  in  various  ways.  When  working  with  the  ordi- 
nary grinding  apparatus,  the  wood  is  prepared  in  exactly 
the  same  manner  as  the  ordinary  material,  i.  e.,  it  is  freed 
from  bark,  the  knots  are  cut  out,  and  the  blocks  are 
finally  cut  into  lengths  to  fit  the  pockets  of  the  machine, 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PULP.-  45 

and  split.  The  blocks  are  then  brought  into  the  boiler  and 
for  8  to  12  hours  treated  with  steam  of  4  to  6  atmospheres. 
The  higher  the  tension  of  the  steam  and  the  longer  the 
wood  is  exposed  to  it,  the  more  energetic  its  action  upon 
the  encrusting  substance  and  the  darker  the  color  of  the 
wood  will  be. 

On  subjecting  steamed  wood  to  a  microscopical  examina- 
tion, it  will  be  found  that  the  greater  portion  of  the  en- 
crusting substance  has  disappeared  and  that  the  vascular 
bundles  consisting  of  cellulose  are  quite  uncovered.  By 
long-continued  steaming  under  high  pressure,  it  might  be 
possible  to  bring  all  the  encrusting  substance  into  solution, 
and  thus  obtain  a  product  which  does  not  essentially  differ 
from  pure  cellulose.  However,  in  practice,  this  process 
cannot  be  profitably  applied  because,  on  the  one  hand,  by 
long-continued  steaming  under  high  pressure,  a  portion  of 
the  cellulose  itself  is  hydrolized,  causing  a  considerable  re- 
duction in  the  yield,  and  on  the  other,  the  cost  of  produc- 
tion is  much  increased.  Hence  steaming  is  continued  only 
long  enough  for  the  wood  to  acquire  a  sufficient  degree  of 
softness,  when  it  is  submitted  to  the  grinding  machine. 
In  grinding  steamed  wood  much  less  power  is  required 
than  in  working  the  raw  material,  which  is  readily  ex- 
plained by  the  breaking-up  of  the  coherence  of  the  vascular 
bundles  by  steaming. 

PREPARATION    OF    MECHANICAL    WOOD-PULP    BY    THE 
CRUSHING    PROCESS. 

A  process — called  by  the  inventor  the  crushing  process — 
for  the  preparation  of  pulp  from  steamed  wood  without  the 
necessity  of  .grinding,  has  been  invented  by  Rasch-Kirchner 
of  Frankfort-on-the-Main. 

The  steamed  wood  to  be  worked  is  first  converted  into 
small  pieces  by  means  of  a  chopping  machine  of  original 
construction,  the  arrangement  of  which  is  shown  in  Figs. 
19,  20,  and  21.  In  a  strong  iron  frame,  K,  rests  in  the 


46 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


bearing,  L,  the  shaft,  A,  which  carries  a  heavy  disk-knife, 
M.  The  latter  in  revolving  passes  the  box,  D,  and  by 
means  of  the  knife,  p,  cuts  the  wood  only  lengthways  into 
shavings  of  fixed  size,  or  lengthways  as  well  as  crossways, 
if  the  cross-slitters,  o,  are  at  the  same  time  applied.  The 
construction  of  the  machine  is  such  as  to  allow  of  its  being 
set  so  that  the  wood  can  be  cut  up  in  different  ways.  The 
wood  may  be  placed  in  an  oblique  position  and  the  cross- 

FIG.  19. 


sections  thus  ^obtained  can  readily  be  reduced  to  pieces. 
By  placing  the  wood  so  tha.t  it  is  worked  perpendicularly 
to  its  length  and  bringing  the  knives  which  serve  for  the 
production  of  cross-slits  into  activity,  shavings  If  inches 
wide  and  long  and  from  0.11  to  0.19  inch  thick  may  be 
obtained. 

The  small  pieces  of  wood  coming  from  the  machine  are 
then  still  further  reduced  by  mechanical  means,  they  being 


WOOD-STUFF,  OR    MECHANICAL    WOOD-PUt,?. 


47 


first  subjected  to  the  action  of  a  stamping  mill  in  which 
they  are  reduced  to  such  a  degree  that  they  can  be  trans- 
ferred to  the  hollander,  a  machine  used  in  paper  mills  for 
the  disintegration  of  paper-stuff.  In  this  apparatus  the. 
mass  may  be  worked  till  it  has  become  sufficiently  uniform 
for  the  direct  preparation  of  boards  in  the  board  machine. 
If,  however,  loose  pulp  is  to  be  pioduced,  the  sorters  em- 

Fio.  20. 


ployed  for  ground  wood  have  to  be  used  in  order  to  sepa- 
rate the  coarser  particles  from  the  finer  fibres. 

However,  the  course  most  generally  pursued  in  working 
the  mass  obtained  from  steamed  wood,  is  to  manufacture 
from  it  at  once  brown  boards  or  stout  wrapping  paper.  A 
pulp  with  longer  fibres  being  more  readily  obtained  from 
steamed  wood  than  from  wood  not  steamed,  boards  and 
paper  made  from  it  possess  greater  strength,  the  boards 
being  especially  suitable  for  roofing  purposes.  Roofs  cov- 


48 


'CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


ered  with  such  boards  properly  impregnated  with  coal-tar 
possess  great  capability  of  resisting  the  action  of  the 
weather,  being  perfectly  indifferent  to  water  as  well  as  to 
changes  in  temperature. 

Numerous  attempts  have  been  made  to  bleach  the  pulp 
from  steamed  wood,  but  thus  far  without  satisfactory  re- 
sults, no  effect  worth  speaking  of  being  produced  on  it  even 
by  the  most  powerful  bleaching  agents.  It  is  very  likely 

FIG.  21. 


that  the  coloring  bodies  formed  in  steaming  wood  belong  to 
the  group  of  combinations  to  which  the  term  humus  bodies 
has  been  applied.  They  are  distinguished  by  a  very  dark 
brown  to  black  color  which  it  is  impossible  to  lighten  up 
by  any  bleaching  agent.  « 

Physically,  ground  wood  actually  differs  from  the  orig- 
inal material  only  in  that  the  individual  vascular  bundles 
appear  to  be  quite  completely  separated  one  from  the  other. 


WOOD-STUFF,  OK    MECHANICAL    WOOD-PULP.  49 

However,  the  individual  vessels  adhering  together  are  still 
firmly  connected  by  the  encrusting  substance — the  lignin — 
this  fact  being  shown  by  storing  the  pulp  for  some  time 
exposed  to  the  light,  it  acquiring  in  a  short  time  a  quite 
strong  brownish  coloration.  This  coloration  also  appears 
in  the  paper-mass  to  which  the  pulp  has  been  added. 
Paper  thus  prepared  turns  perceptibly  brown  when  for  a 
few  weeks  exposed  to  the  light,  and  at  the  same  time  be- 
comes brittle.  The  manufacture  of  paper  which  could  lay 
claim  to  durability  for  a  longer  time  would  therefore  ap- 
pear impossible  with  the  use  of  larger  quantities  of  mechan- 
ical wood-pulp,  it  being  possible  only  when  pure  cellulose, 
the  great  stability  of  which  has  previously  been  referred  to, 
is  employed. 
4 


III. 

PREPARATION  OF  CELLULOSE  FROM  WOOD. 

(WOOD-CELLULOSE,  CELLULOSE  IN  THE 

TECHNICAL  SENSE  OF  THE  WORD, 

CHEMICAL  WOOD-PULP.) 

Paper  consists  of  cellulose  fibres  felted  together  in  a  pe- 
culiar manner  so  that  the  individual  fibres  can  no  longer 
be  distinguished.  The  cellulose  which  was  formerly  ex- 
clusively used  for  the  manufacture  of  paper  consisted  of 
waste  of  linen  and  cotton  fabrics,  and  other  vegetable 
fibrous  substances.  By  reason  of  the  constant  increase  in 
the  consumption  of  paper,  the  price  of  this  waste,  technically 
called  rags,  rose  steadily,  so  that  the  efforts  of  chemists 
were  for  a  long  time  directed  towards  finding  a  substitute 
for  rags  in  another  vegetable  substance.  After  many  ex- 
periments, the  results  of  which,  however,  were  not  very 
satisfactory,  a  process  was  finally  discovered  which  allowed 
of  the  separation  of  cellulose  from  certain  varieties  of  wood 
in  such  a  form  as  to  render  it  suitable  for  use  in  the  manu- 
facture of  paper.  The  production  of  cellulose  from  wood 
has  now  become  a  highly  developed  industry,  and  every 
year  the  quantity  of  raw  material  worked  up  becomes  larger. 

In  the  preparation  of  cellulose  from  wood,  the  principal 
point  is  the  removal  of  the  substances  which  incrust  the 
cellulose,  and  to  convert  the  latter  into  actual  wood  sub- 
stance, as  well  as  to  obtain  it  in  a  pure  form.  It  is,  how- 
ever, also  of  importance  that  the  individual  fibres  should 
be  of  a  certain  length  to  allow  of  them  being  properly 
felted  together  into  paper,  and  the  solution  of  this  demand 

(50) 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.        51 

presented  for  a  long  time  many  difficulties  which,  however, 
finally  were  successfully  overcome. 

There  are  quite  a  number  of  methods  by  which  wood 
cellulose  may  be  prepared,  but  only  three  of  them — namely, 
the  soda  process,  the  sulphite  process  and  the  electric  pro- 
cess— have  at  present  been  firmly  established  in  practice. 
The  sulphite  process,  while  it  yields  the  same  favorable  re- 
sults, is  far  more  simple  in  execution  than  the  soda  process, 
and  is  more  and  more  replacing  the  latter,  many  wood- 
cellulose  plants  at  present  working  exclusively  with  it. 

Since  the  encrusting  substance  of  the  wood  may  also  be 
destroyed  by  acids,  a  series  of  processes  have  from  time  to 
time  been  introduced,  the  object  of  which  is  to  effect  the 
disintegration  of  the  wood-fibre  by  their  use,  concentrated 
nitric  acid,  as  well  as  aqua  regia — a  mixture  of  nitric  and 
hydrochloric  acids — having  been  employed  for  the  purpose. 
However,  independent  of  the  great  expense  connected  with 
them,  these  processes  have  the  further  disadvantage  that 
it  seems  next  to  impossible  to  keep  the  operating  vessels 
tight,  in  consequence  of  which  products  of  decomposition 
of  nitric  acid  escape  into  the  work-room,  rendering  the  air 
of  the  latter  very  injurious  to  the  health  of  the  workmen. 
For  these  reasons,  this  method  of  preparing  cellulose  has 
been  entirely  abandoned.  It  may,  however,  be  mentioned 
that  one  acid  process  by  which  the  disintegration  of  the 
wood  is  effected  with  hydrochloric  acid,  would  seem  to  be 
available,  since  it  yields  a  very  valuable  by-product. 

BACHET  AND  MACHARD's  METHOD. 

According  to  this  method  thin  slices  of  fir  are  subjected 
to  hot  treatment  with  hydrochloric  acid.  Four  thousand 
eight  hundred  pounds  of  fir  in  thin  slices  are  brought  into 
a  wooden  vessel  and  after  pouring  over  them  2000  gallons 
of  water  and  1760  Ibs.  of  hydrochloric  acid,  the  fluid  is 
brought  to  boiling  by  the  introduction  of  steam,  boiling 
being  continued  for  12  hours.  The  fluid  is  then  drawn  off 


52  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

and  neutralized  with  calcium  carbonate.  It  now  represents 
a  dilute  solution  of  grape  sugar  which  can  be  brought  by 
yeast  into  vinous  fermentation,  and  by  distillation  yields  a 
considerable  quantity  of  alcohol.  The  residue  consisting 
of  cellulose  is  washed  with  water  until  all  the  acid  is  re- 
moved, crushed  under  millstones  and  disintegrated  in  the 
hollander.  Since  by  this  process  a  considerable  portion  of 
the  cost  of  manufacture  is  covered  by  the  alcohol  gained 
as  a  by-product,  it  would  appear  to  be  of  importance  for  the 
practice.  To  judge,  however,  from  its  present  state,  this 
method  has  many  inherent  defects  which  prevent  its  gen- 
eral introduction.  If,  however,  these  defects  can  be  over- 
come, it  might  prove  of  importance  for  the  manufacture  of 
cellulose.  Later  on  more  modern  processes  for  obtaining 
alcohol  from  wood  will  be  referred  to. 

PREPARATION  OF  CELLULOSE  BY  MEANS  OF  SODA. 

This  method  of  preparing  cellulose  is  an  American  in- 
vention— poplar,  pine,  spruce,  and  occasionally  birch,  being 
used  for  the  purpose.  Poplar  is  especially  distinguished 
from  other  woods  in  yielding  very  long-fibered  cellulose. 
This  process  which  may  be  called  the  American  wood-pulp 
system  can  also  be  profitably  applied  to  the  conifers  indig- 
enous to  Europe. 

The  first  step  in  the  manufacture  is,  in  all  cases,  the 
mechanical  preparation  of  the  wood  to  be  worked.  This 
consists  in  carefully  freeing  the  wood,  cut  up  into  short 
blocks  from  the  bark,  cutting  out  the  knots  by  special 
machinery  and  reducing  the  blocks  to  chips  about  f  inch 
long,  J  inch  wide,  and  0.19  to  0.31  inch  thick.  All  the 
mechanical  operations :  Freeing  from  bark,  cutting  out 
knots,  etc.,  are  carried  out  by  special  machines. 

The  disintegration  of  the  encrusting  substance  of  the 
wood  is  effected  by  means  of  caustic  soda  lye.  The  state- 
ments regarding  the  quantities  of  soda  lye — relatively  of 
caustic  soda — required  for  working  220  Ibs.  of  wood  vary 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.        53 

very  much,  but  the  quantity  of  caustic  soda  obtained  from 
48.4  Ibs.  of  carbonate  of  soda  is  said  to  be  sufficient  in  all 
cases.  By  the  action  of  the  caustic  soda,  the  encrusting 
substance  of  the  wood  is  destroyed  and  the  resins  are 
saponified.  When  the  process  of  disintegration  is  finished, 
the  fluid  is  discharged  and  evaporated  in  iron  pans  to  dry- 
ness.  The  residue  is  heated  in  a  reverberatory  furnace 
whereby  the  acids  fixed  to  the  soda  are  destroyed,  carbonate 
of  soda  remaining  finally  behind.  This  carbonate  of  soda 
is  again  converted  into  caustic  soda,  so  that  for  the  next 
operation  only  a  sufficient  quantity  of  fresh  caustic  soda  to 
replace  that  unavoidably  lost  in  the  wash  waters  is  required. 

Sodium  sulphite  having  the  same  destructive  effect  upon 
the  encrusting  substance  as  caustic  soda,  it  is  frequently 
substituted  for  a  portion  of  the  latter.  This  is  effected  by 
evaporating  the  lye  which  has  once  been  used  for  boiling 
the  wood,  together  with  sodium  sulphate,  which  is  quite 
cheap,  and  heating  the  residue.  By  the  carbonization  of 
the  organic  combinations  contained  in  the  salt-mass,  the 
sodium  sulphate  is  reduced  to  sodium  sulphite  and  a  fluid 
is  obtained  which,  when  again  made  caustic,  contains,  in 
addition  to  caustic  soda,  a  certain  quantity  of  sodium 
sulphite. 

To  free  the  chips  of  wood  from  the  encrusting  substance 
by  boiling  them  with  soda  lye  in  open  vessels,  would  re- 
quire so  much  time  as  to  make  the  process  scarcely  avail- 
able for  practical  purposes.  If,  however,  the  lye  is  allowed 
to  act  under  increased  pressure  upon  the  wood,  disintegra- 
tion will  be  accomplished  in  a  comparatively  shorter  time 
and  with  greater  rapidity,  the  greater  the  pressure  is  and 
the  higher  the  temperature  prevailing  in  the  apparatus. 
In  practice  a  pressure  from  6  to  14  atmospheres  is  used, 
though  one  from  10  to  11  atmospheres  is  most  frequently 
employed. 


54 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


FIG.  22. 


SINCLAIR'S  BOILER. 

From  what  has  been  said  above,  the  construction  of  the 
boiling  apparatus  must  be  such  as  to  be  capable  of  resisting 
the  high  pressure  prevailing  in  its  interior,  as  its  explosion 
might  cause  terrible  accidents.  Since,  considering  the  size 
of  the  boilers,  even  if  constructed  of  the  best  quality  of 
steel,  it  is  difficult  to  keep  them  tight  under  the  high  pres- 
sure, of,  say  14  atmospheres,  prevailing  in  them,  an  ingen- 
ious contrivance  to  de- 
crease the  pressure  is  made 
use  of  in  Sinclair's  boiler, 
the  actual  boiler  being 
enclosed  by  another  boiler 
also  made  of  steel.  In 
the  inner  boiler  in  which 
the  soda  lye  acts  upon  the 
wood,  prevails  a  pressure 
of  14  atmospheres,  while 
in  the  space  between  the 
inner  and  outer  boilers 
circulates  steam  of  6  at- 
mospheres, and  hence  the 
pressure  upon  the  wall  of 
the  inner  boiler  is  reduced 
to  8  atmospheres.  The 
arrangement  of  Sinclair's 
boiler  is  shown  in  Fig.  22. 
The  vertical  boiler  con- 
sists of  a  cylindrical  vessel 
A  tapering  above  and  be- 
low. In  this  vessel  stands  a  second  one  B,  of  the  same 
form,  which,  however,  is  constructed  of  thin  sheet  iron,  and 
its  surface  is  perforated  with  holes.  Its  diameter  is  such 
that  the  walls  of  B  are  at  a  distance  of  1.18  to  1.57  inch 
from  A.  B  is  the  portion  of  the  apparatus  which  serves  for 
the  reception  of  the  wood.  The  boiler  is  charged  through 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       55 

the  aperture  C,  and  after  the  operation  is  finished,  the  fluid 
is  discharged  through  the  pipe  d.  The  vessel  G  serves  as 
a  storage  reservoir  for  soda  lye  and  is  so  arranged  as  to 
allow  of  the  introduction  of  lye  into  the  boiler  during  the 
operation  without  a  decrease  in  the  pressure  taking  place. 
When  lye  is  to  be  introduced,  the  lower  cock  h  is  first 
opened,  and  then  the  upper  one  hi.  The  same  pressure 
then  prevails  in  the  vessel  G  as  in  the  boiler  and  lye  may 
run  into  the  latter.  The  entire  apparatus  is  heated  by  an 
open  fire  from  the  fire-place  F.  The  lower  portion  of  the 
boiler  is  protected  by  brickwork  to  prevent  its  coining  in 
direct  contact  with  the 'flame.  The  flames  pass  upwards 
through  special  flues  which  are  so  arranged  that  the  flames 
come  on  every  side  in  contact  with  the  boiler. 


In  some  systems  of  boiling  wood  an  entire  battery  of 
boiling  vessels,  one  connected  with  the  other,  is  used  in- 
stead of  a  single  boiler.  When  the  boilers  have  been  filled 
with  wood,  soda  lye  is  introduced  into  the  first  one,  and 
allowed  to  act  upon  the  wood  for  some  time,  for  instance, 
one  hour.  Fresh  lye  is  then  introduced  into  the  first  boiler 
in  such  a  way  that  the  fluid  contained  in  it  is  forced  into 
the  second  boiler.  In  about  one  hour  fresh  lye  is  again 
brought  into  the  first  boiler,  the  lye  contained  in  the  second 
boiler  being  forced  into  the  third  one,  and  so  on.  Hence 
the  wood  is  constantly  treated  with  fresh  lye,  and  disinte- 
gration is  effected  more  completely  and  in  a  shorter  time 
than  when  the  wood  is  always  boiled  with  the  same  quan- 
tity of  lye.  The  system  sketched  above  has  been  intro- 
duced by  Ungerer.  In  its  arrangement  the  apparatus 
closely  resembles  the  diffusion  apparatuses  used  in  sugar 
houses  and  in  factories  for  the  preparation  of  dye  extracts. 
It  seems  probable  that  by  this  method  the  object  of  the  dis- 
integration of  the  wood  might  be  accomplished  with  cer- 
tainty and  in  the  shortest  time. 


56  CELLULOSE,  AND  CELLULOSE  PRODUCTS. 

KEEGAN'S  PROCESS. 

This  process  for  the  disintegration  of  the  wood  by  means 
of  caustic  soda,  differs  essentially  from  the  methods  in 
which  the  wood  is  heated  under  high  pressure  with  soda 
lye.  The  process  in  its  distinctive  features  consists  in  that 
the  wood  is  brought  into  a  vessel  from  which  the  air  is  ex- 
hausted. The  cold  soda  lye  is  then  introduced  and  the 
pressure  upon  the  fluid  raised  to  3J  atmospheres.  When 
it  is  supposed  that  the  wood  is  completely  saturated  with 
soda  lye,  the  lye  not  absorbed  is  allowed  to  run  off  and  the 
vessel  is  heated  to  302°  F.  The  quantity  of  soda  lye 
absorbed  by  the  vessels  of  the  wood  suffices  to  bring  into 
solution  all  the  encrusting  substances,  and  one  great  ad- 
vantage of  this  process  is  that  the  wood  treated  with  lye 
need  only  be  washed  with  a  small  quantity  of  water  in 
order  to  regain  from  it  the  greater  portion  of  the  soda. 
Hence  only  a  comparatively  small  quantity  of  fluid  has  to 
be  evaporated,  thus  saving  considerable  in  operating  ex- 
penses, since  the  great  consumption  of  fuel  conditional  to 
the  evaporation  of  a  large  quantity  of  lye  is  one  of  the 
drawbacks  of  the  process  of  producing  cellulose  by  means 
of  caustic  soda. 

The  mass  of  wood  boiled  according  to  one  of  the  methods 
above  described,  consists  of  cellulose,  the  interspaces  of 
which  are  filled  with  the  fluid  which  has  been  formed  from 
the  soda  lye  and  the  substances  absorbed  by  it.  The  next 
problem  is  to  obtain  this  fluid  as  completely  as  possible,  so 
that  the  soda  contained  in  it  may  again  be  brought  into 
use.  However,  so  as  not  to  use  too  much  fuel  for  evaporat- 
ing the  lye,  the  recovery  of  the  soda  should  at  the  same 
time  be  effected  in  such  a  manner  that  as  little  fluid  as 
possible  is  obtained.  In  order  to  attain  this  object  as  com- 
pletely as  possible,  the  system  of  gradual  lixiviation  em- 
ployed everywhere  in  chemical  establishments  when  a  solid 
body  has  to  be  entirely  freed  from  adhering  fluid,  is  made 
use  of  in  cellulose  plants. 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.        57 

In  working  according  to  this  method  a  battery  has  to  be 
used  in  which  lixiviation  is  effected  by  means  of  a  current. 
The  distinctive  features  of  such  an  apparatus  are  as  follows  : 
A   number  of  vessels — ten  to    twelve — are  connected  one 
with  the  other  in  such  a  way  that  when  the  level  of  the 
fluid  in  the  first  vessel  reaches  a  certain  height,  the  fluid 
running  off  rises  from  the  bottom  through  a  pipe  and  can 
flow  into  the  next  vessel.     When  these  vessels  are  filled 
with  the  mass  coming  from  the  boiler  and  water  is  poured 
into  the  first  vessel,  it  will  in  a  short  time  become  mixed 
with  the   fluid  contained  in  the  mass  of  wood.     By  now 
allowing  more  water  to  run  into  the  vessel,  the  fluid  con- 
tained in  it  is  forced  into  the  next  vessel  where  it  becomes 
more  enriched  with  soda.     Now,   with    the  use  of  twelve 
lixiviating  vessels,  the  mass  in  the  first  vessel  will   have 
been  twelve  times  in  contact  with  water  at  the  time  when 
the  last,  vessel  has  just  been  filled.     When  water  is  then 
again  poured  into  the  first  vessel,  a  corresponding  quantity 
of  fluid  will  run  off  from  the  twelfth  vessel.     This  fluid  is 
a  very  saturated  soda  solution,  and  the  quantity  of  soda 
contained  in  it  corresponds  with  that  present  in  the  fluid 
discharged  from  the  boiler.     The  mass  of  cellulose  in  the 
first  vessel  is  now  completely  washed  and  can  be  immedi- 
ately subjected  to  further  working  by  mechanical  means. 

While  the  first  vessel  is  being  emptied,  the  course  of  the 
supply  ot  water  is  so  changed  that  the  second  vessel  of  the 
battery  becomes  the  first  and  in  this  manner  lixiviation  is 
systematically  continued. 

A  number  of  contrivances,  such  as  counter-current  wash- 
ing machines,  wash-drums,  etc.,  have  been  introduced  for 
washing  cellulose,  which  do  good  service  provided  they 
fulfill  the  object  of  lixiviating  the  cellulose  mass  in  the 
most  complete  manner,  and  with  the  smallest  possible  con- 
sumption of  water. 


58         CELLULOSE,  AND  CELLULOSE  PRODUCTS. 
PREPARATION  OF  CELLULOSE  BY  MEANS  OF  SODIUM  SULPHITE. 

It  has  been  previously  mentioned  that  in  preparing 
cellulose  with  caustic  soda  a  portion  of  the  latter  may  be 
replaced  by  sodium  sulphate.  This  salt,  to  be  sure,  does 
not  take  part  in  the  process,  but  when  the  used  lyes  are 
evaporated  and  the  residue  is  heated,  it  is  converted  into 
sodium  sulphite,  which,  like  caustic  soda,  has  a  destructive 
effect  upon  the  encrusting  substance  of  the  wood.  Hence, 
in  the  course  of  the  operation,  before  evaporating  the  used 
lyes,  it  is  only  necessary  to  add  to  them  a  determined 
quantity  of  sodium  sulphate  in  order  to  obtain  by  the  re- 
generation of  the  salt,  the  corresponding  quantity  of  sodium 
sulphite.  The  highly  evaporated  lyes  are  mixed  with 
limestone  and  coal-dust,  and  after  drying,  melted  in  a 
reverberatory  furnace,  whereby  caustic  soda  and  sodium 
sulphite  are  obtained.  After  washing  the  salts  with  water, 
they  are  dissolved  and  used  for  boiling.  For  every  100 
parts  of  dry  substance  of  the  lye  used,  100  parts  of  lime- 
stone and  25  parts  of  coal-dust  are  used. 

The  further  working  of  the  washed  cellulose  is  effected 
by  purely  mechanical  means.  As  a  rule,  the  pieces  of 
cellulose,  which  still  retain  largely  the  form  of  the  frag- 
ments of  wood  originally  used,  are  ground  in  a  mill  with 
water  to  a  paste.  This  paste  is  mixed  with  a  large  quan- 
tity of  water  and  made  homogeneous  in  the  hollander.  If 
to  be  used  in  the  manufacture  of  finer  qualities  of  paper  it 
is  also  bleached  with  chlorine.  The  value  of  cellulose  is 
the  greater  the  longer  its  individual  fibres  are,  because  long 
fibres  felt  more  completely  together  than  short  ones,  the 
resulting  paper  being  much  stronger.  However,  generally 
speaking,  finer  qualities  of  paper  are  not  made  from  wood 
cellulose  alone,  the  pulp  for  them  consisting,  as  a  rule,  of 
cellulose  prepared  from  rags  mixed  with  a  certain  per- 
centage of  wood-cellulose. 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.        59 

The  statements  regarding  the  consumption  of  wood  and 
chemicals  in  the  different  factories  vary  so  much  as  to  ren- 
der it  difficult  to  give  a  correct  idea  of  it.  Moreover,  the 
yield  of  cellulose  appears  to  be  essentially  effected  by  the 
content  of  water  in  the  wood  to  be  worked.  The  content 
of  water  in  thoroughly  air-dry  wood  is  about  20  per  cent., 
while  in  many  varieties  of  wood,  when  freshly  cut,  it  may 
amount  to  twice  as  much,  and  for  that  reason  the  yield  of 
cellulose  will  turn  out  quite  different  from  that  calculated 
from  the  weight  of  the  wood.  The  nature  of  the  wood  to 
be  worked  is  also  of  great  influence  upon  the  yield  of  fin- 
ished cellulose,  as  shown  by  the  following  figures  given  by 
Reid: 

Variety  of  wood.  Cellulose  in  per  cent.  Length  of  fibre. 

Beech  38.5  short 

Birch  42.0  short 

Hemlock  spruce  37.5  long 

Poplar  41.7  medium 

Pine  39.0  long 

Fir  38.0  long. 

PREPARATION    OF  CELLULOSE    WITH  THE    ASSISTANCE    OF  SUL- 
PHITES.    (SULPHITE-CELLULOSE  ACCORDING  TO 

MITSCHERLICH'S  PROCESS). 

Solutions  of  acid  sulphites  possess,  similar  to  caustic  alka- 
lies and  their  combinations  with  sulphur,  the  property  of 
dissolving  and  destroying  the  encrusting  substance  of  wood. 
The  process  of  preparing  cellulose  in  this  manner  is  the  in- 
vention of  the  German  chemist  Mitscherlich,  all  other  sul- 
phite processes  being  more  or  less  suitable  modifications  of 
it.  In  establishing  a  sulphite-cellulose  plant  it  is  of  the 
utmost  importance  that  an  abundance  of  water  should  be 
available,  and  besides  the  conditions  must  be  such  that  the 
waste  liquor  can  be  discharged  into  a  water-course  of  consid- 
erable size.  For  the  manufacture  of  4,400  Ibs.  of  air-dry 
cellulose  about  15,000  gallons  of  water  are  required,  and 
the  waste  liquor  of  the  plant  must  be  diluted  to  such  an 


60  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

extent  as  not  to  be  detrimental  to  the  existence  of  animals 
in  the  streams  into  which  it  is  discharged,  since  otherwise 
the  unavoidable  consequence  would  be  that  the  plant 
would  constantly  have  to  pay  large  amounts  for  damages  to 
the  proprietors  of  the  fishing  rights  in  the  respective 
streams,  and  might  even  be  forced  entirely  to  suspend 
operations. 

The  wood  has  to  be  prepared  with  special  care  and 
should  be  used  as  soon  as  possible  after  having  been  cut 
down.  In  case  wood  which  has  been  cut  for  some  time  is 
to  be  worked,  it  should  previously  be  for  a  few  days  placed 
in  water.  Since  there  is  a  difference  in  the  behavior  of  the 
various  kinds  of  wood  toward  the  sulphites,  only  one 
special  variety  should  at  one  operation  be  worked. 

The  trunks  to  be  used  must  be  carefully  freed  from  bark 
and  bast,  and  adhering  dirt  is  to  be  removed,  so  that  only 
perfectly  clean  wood  is  brought  into1  the  saw-mill.  In  the 
latter,  the  trunks  are  cut  by  circular  saws  into  blocks  about 
16  inches  long,  and  the  knots  cut  out  by  a  suitable 
machine.  Finally  the  blocks  are  cut  up  into  thin  discs  not 
more  than  1  inch  thick,  which  are  again  inspected,  pieces 
with  knots  in  them  being  rejected.  In  preparing  the  wood 
in  the  manner  above  described  there  will  naturally  be  con- 
siderable waste,  and  besides  a  large  quantity  of  sawdust. 
The  latter,  to  be  sure,  can  be  worked  together  with  the 
discs,  but  readily  causes  annoyance  and  trouble  by  obstruct- 
ing pipes,  etc.  Hence,  in  many  plants  the  practice  of 
cutting  the  blocks  into  discs  has  been  entirely  abandoned, 
the  blocks  being  converted  by  a  machine  resembling  a 
planing  machine,  into  thin  boards  0.27  to  0.29  inch  thick, 
an  essential  advantage  of  this  procedure  being  that  the 
longitudinal  fibres  of  the  wood  are  preserved  and  cellulose 
of  greater  length  can  be  obtained. 

Pine  is  considered  the  best  material  for  the  preparation 
of  sulphite  cellulose,  and  next  to  it,  fir  is  most  highly 
valued.  Scotch  fir,  to  be  sure,  is  also  suitable  for  the  pur- 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.        61 

pose,  but  only  the  sap-wood  should  be  used,  the  heart 
yielding  cellulose  of  a  dark  color.  Other  varieties  of  wood, 
including  deciduous  trees,  may  also  be  used,  but  the  cellu- 
lose obtained  from  them  is  not  as  strong  as  that  from  coni- 
fers, and  the  yield  of  finished  cellulose  is  small. 

The  preparation  of  cellulose  by  the  sulphite  process  may 
be  divided  into  three  principal  operations : 
I.  Preparation  of  the  sulphite  solution. 
II.  Boiling  the  prepared  wood  with  the  solution. 

III.  Treatment  of  the  cellulose  mass  obtained. 

PREPARATION  OF  THE  SULPHITE  SOLUTION. 

According  to  Mitscherlich's  process,  the  incrusting  sub- 
stance of  the  wood  is  dissolved  by  the  use  of  solution  of 
calcium  bisulphite,  obtained  by  treating  calcium  carbonate 
with  sulphurous  acid.  The  operation  is  carried  out  as  fol- 
lows : 

Sulphurous  acid  in  gaseous  form  is  conducted  into  a 
vessel  filled  with  porous  limestone,  water  being  at  the 
same  time  allowed  to  flow  over  the  limestone.  From  the 
limestone,  from  which  the  carbonic  acid  has  been  expelled, 
neutral  calcium  sulphite  is  first  formed.  However,  since 
sulphurous  acid  is  present  in  excess,  it  ascends  in  the  ves- 
sel, dissolves  in  the  water  trickling  down -and  flows  back 
over  the  neutral  calcium  sulphite,  which,  as  it  dissolves 
with  greater  difficulty  than  the  limestone,  has  settled  upon 
the  latter.  Calcium  bisulphite,  which  dissolves  with  ease, 
is  now  formed,  and  the  resulting  solution  of  this  salt  runs 
off  into  a  collecting  reservoir.  In  cellulose,  plants  this 
solution  is  briefly  called  lye,  and  by  this  term  it  will  be 
referred  to  throughout  the  succeeding  pages. 

Very  large  quantities  of  iye  being  required  in  a  cellulose 
plant,  the  apparatus  for  its  preparation  must  be  of  ade- 
quate size.  In  reference  to  this,  Mitscherlich,  who  has 
worked  out  to  the  smallest  details  the  entire  operation  of 
this  process,  makes  the  following  important  statements: 


-  62  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

The  limestone  serving  for  the  preparation  of  the  lye 
should  be  as  pure  as  possible,  so  that  not  too  much  mud  is 
formed  by  foreign  substances  (magnesia  or  organic  sub- 
stance) contained  in  it.  It  should  further  be  very  porous 
and  at  the  same  time  firm,  so  as  not  to  be  crushed  by  the 
weight  of  the  layer  over  it,  which  might  cause  troublesome 
obstructions  in  the  apparatus.  A  material  which  can  be 
recommended  for  the  purpose  is  solid  tufaceous  limestone 
in  pieces  about  the  size  of  the  fist,  which  are  piled  up  to  the 
height  of  39.37  inches  in  the  tower-like  structure  in  which 
the  lye  is  prepared.  To  prevent  the  pieces  of  limestone 
from  packing  too  closely  together  and  crumbling  in  falling 
down  the  entire  height  of  the  tower,  the  latter  is  filled  to  a 
certain  depth,  and  a  fresh  charge  equal  in  size  to  the  orig- 
inal one  is  introduced  from  the  top  of  the  tower  when  the 
layer  of  limestone  has  sunk  to  a  certain  depth. 

The  sulphurous  acid  required  for  the  preparation  of  the 
lye  is  obtained  by  burning  sulphur  or,  if  cheaper,  pyrites. 
Sulphur-burning  is  an  operation  requiring  careful  regula- 
tion, so  that  combustion  is  complete  and  no  unburnt  sul- 
phur reaches  the  absorbing  tower.  One  of  the  best  tests  in 
this  respect  is  the  color  of  the  flame,  which  should  be  pure 
blue.  The  appearance  of  a  yellow,  dark  flame  is  an  indi- 
cation of  an  insufficient  admission  of  oxygen,  the  conse- 
quence of  which  is  generally  an  evaporation  of  unburnt 
sulphur  which  may  damage  the  pipes  and  become  very 
troublesome.  Incomplete  combustion  of  the  sulphur  may 
be  due  to  an  inadequate  supply  of  air  to  the  furnace  itself, 
but  it  may  also  be  caused  by  the  current  of  gas  ascending 
in  the  absorbing  tower  not  being  strong  enough,  and  hence 
the  entire  apparatus  needs  careful  watching.  In  order  to 
have,  in  addition  to  the  appearance  of  the  flame,  a  means 
of  testing  whether  sulphur  in  the  form  of  -vapor  is  carried 
along  with  the  sulphurous  acid,  a  wide  glass  tube,  /,  Fig. 
23,  is  inserted  in  the  pipe  through  which  the  sulphurous 
acid  is  conducted,  a  portion  of  the  latter  passing  through 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.        03 

the  glass  tube,  and  the  appearance  of  a  yellow  tinge  in  the 
latter  is  an  indication  of  a  content  of  unburnt  sulphur  in 
the  gas.  The  arrangement  of  the  absorbing  tower  in  which 
the  formation  of  the  lye  takes  place  is  shown 
in  Figs.  24  and  25.  The  pipe  through 
which  the  sulphurous  acid  is  conducted 
from  the  furnace  k  should  rise  at  least  two- 
thirds  the  height  of  the  tower,  then  turn 
downward  at  a  right  angle  and  enter  the 
tower  from  below.  The  ascending  portion 
a  of  this  pipe  is  constructed  of  iron,  while 
the  descending  portion  b  consists  generally 
of  tile-pipe.  The  nearly  horizontal  portion 
of  the  pipe  through  which  the  gas  enters 
the  tower  must  by  all  means  consist  of  tile-pipe.  The 
diameter  of  the  pipe  should  be  such  that  the  gases  are  not 
exposed  to  considerable  friction  and  may  sufficiently  cool 
off  before  entering  the  tower. 

The  absorbing  tower  is  105  feet  high  and  about  5  feet 
square.  It  is  constructed  of  wood,  very  resinous  wood,  for 
instance,  Scotch  fir  or  pitch  pine,  being  used.  Larch  being 
expensive  is  more  seldom  employed.  The  walls  of  the 
tower  must  be  thick,  the  lower  portion  being  made  3.15 
inches,  the  centre  portion  2.36  inches  and  the  upper  portion 
1.57  inches  thick.  The  separate  parts  of  wood  are  held 
together  by  stout  iron  hoops  secured  by  screws,  they,  as  well 
as  the  screws,  being  carefully  coated  with  tar.  Joints  be- 
tween the  parts  of  wood  are  stuffed  with  tow  and  coated 
with  tar. 

The  lower  portion  of  the  tower  is  furnished  with  a  grate  h 
of  oak  beams,  which  must  be  strong  enough  to  support  the 
load  of  the  layer  of  limestone  placed  upon  it.  Between  the 
grate  beams  are  openings  2.95  inches  wide  through  which 
the  gases  ascend  and  the  lye  runs  down.  The  upper  faces 
of  the  beams  are  2.95  inches  wide,  but  the  lower  ones  only 
1.96  inches.  Two  oak  beams  are  also  placed  in  the  tower 


64 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


3J  feet  above  the  grate  for  the  purpose  of  partially  relieving 
the  latter.      Boards    placed    horizontally   are   secured   by 


FIG.  24. 


FIG.  25. 


means  of  stout  wooden   pegs  to  the'walls  of  the  tower  at 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       65 

distances  of  3J  feet  one  above  the  other.  These  boards 
slope  inward,  so  that  the  fluid  dripping  down  upon  them  is 
conducted  towards  the  interior  of  the  tower  and  the  walls 
of  the  latter  are  not  moistened.  Figs.  26  and  27  show  on 
an  enlarged  scale  the  shape  of  these  boards  and  the  manner 
of  fastening  them. 

Large  as  such  a  tower  is,  it  is  scarcely  of  sufficient  size 
to  prepare  in  it  the  lye  required  for  one  boiler.  In  order 
to  carry  on  operations  without  interruption  and  to  be  able 
occasionally  to  clean  a  tower  which  has  been  in  use  for  a 

FIG.  26.  FIG.  27. 


longer  time,  it  would  seem  to  be  advisable  to  build  four 
towers,  erecting  one  on  each  corner  of  a  square,  and  placing 
the  stairs,  water  pipe  and  hoist  for  the  limestone  in  the 
square.  Reservoirs  for  the  reception  of  the  lye  which  is 
discharged  through  a  lead  pipe  from  the  tower  are  located 
alongside  the  latter.  The  lead  pipe  is  placed  slightly  above 
the  bottom  of  the  tower  and  is  bent  at  a  very  obtuse  angle 
like  a  siphon,  thus  forming  a  hydraulic  joint  which  allows 
of  the  lye  running  off,  but  prevents  the  escape  of  gas  from 
the  tower.  The  lye  first  passes  through  the  lead  pipe  into 
a  barrel  open  at  the  top  and  divided  into  two  compartments 
by  a  partition  reaching  half-way  up.  The  greater  portion 
of  the  mud  carried  along  by  the  fluid  settles  on  the  bottom 
5 


66  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

of  the  barrel.  From  the  bottom  of  this  barrel  the  fluid 
passes  through  a  lead  pipe  into  another  barrel  filled  with 
small  pieces  of  limestone  in  which  the  small  quantity  of 
free  sulphurous  acid,  which  may  still  be  contained  in  the 
lye,  is  fixed.  After  passing  through  this  barrel,  the  lye 
runs  into  the  actual  lye-reservoirs. 

Large,  prismatic,  wooden  boxes,  16J  feet  wide,  10  feet 
deep  and  23  feet  long,  serve  for  lye  reservoirs,  at  least  two 
of  which  should  be  provided  for  every  boiler.  The  lye  con- 
tained in  one  of  these  reservoirs  being  just  sufficient  for  one 
boiling,  the  two  reservoirs  are  connected  by  a  wooden  pipe 
so  arranged  that  the  connection  can  be  cut  off  for  the  pur- 
pose of  cleaning  one  reservoir  while  the  latter  is  being  filled. 
The  conduits  leading  from  the  reservoirs  to  the  boiler  are 
also  constructed  of  tarred  wood,  this  material  being  more 
capable  of  resisting  the  action  of  the  lye  than  all  others, 
even  not  excepting  lead. 

In  preparing  the  lye  care  must  be  taken  that  the  sulphur- 
ous acid  obtained  by  combustion  reaches  the  tower  entirely 
cooled  off.  When  the  odor  of  sulphurous  acid  commences 
to  be  perceptible  at  the  upper  aperture  of  the  tower,  water 
is  introduced  from  the  reservoir  ra  placed  at  a  higher  level, 
and  the  supply  is  so  regulated  that  the  odor  of  sulphurous 
acid  can  just  be  noticed,  the  object  in  view,  namely,  to  ob- 
tain a  lye  as  concentrated  as  possible  being  in  this  manner 
most  assuredly  attained.  In  case  an  irregularity  should 
occur  in  the  course  of  the  operation,  it  is  either  due  to  the 
sulphurous  acid  carrying  along  with  it  vapors  of  sulphur, 
or  the  supply  of  water  is  too  small,  so  that  the  neutral  cal- 
cium sulphite  formed  upon  the  pieces  of  limestone  cannot 
be  converted  into  the  readily-soluble  acid  combination,  or, 
finally,  it  may  be  caused  by  the  current  of  gas  being  ob- 
structed in  the  tower.  In  this  case  a  remedy  must  at  once 
be  applied  and  an  effort  be  made  to  overcome  the  disturb- 
ance by  a  stronger  supply  of  water  kept  up  for  some  time. 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.        67 

1  I       . 

BOILING    THE    WOOD    WITH    THE  LYE. 

The  object  of  this  operation  is  to  bring  into  solution  the 
encrusting  substance  and  convert  the  wood  into  cellulose. 
For  this  purpose  a  large  iron  vessel  or  boiler  of  cylindrical 
shape,  Figs.  28  and  29,  is  used,  which  is  furnished  with 
four  manholes,  two  on  top  and  two  on  the  bottom.  All  the 
fixtures  for  the  introduction  of  lye,  steam,  etc.,  are  placed 
on  the  lids  of  the  manholes,  because  they  can  be  more 
readily  kept  tight  there  than  in  any  other  place.  To  pre- 
vent the  lye  from  coming  in  direct  contact  with  the  iron, 
the  latter  being  strongly  attacked  by  it,  the  interior  surface 
of  the  boiler  is  first  coated  with  a  mixture  of  pitch  and 
common  tar,  the  proportions  of  the  mixture  being  such 

FIG.  28. 


that,  when  heated  the  coat  is  quite  thinly-fluid,  but  very 
sticky  at  the  ordinary  temperature.  Upon  this  coat  is  laid 
a  thin  layer  of  sheet-lead,  at  least  0.07  inch  thick,  and 
rubbed  down  smoothly  so  that  the  interior  surface  of  the 
boiler  appears  to  be  lined  with  lead.  The  portions  of  the 
boiler  which  have  to  be  moved — the  lids  of  the  manholes, 
etc. — are  provided  with  a  double  protecting  covering  of 
thicker  sheet-lead.  The  interior  space  of  the  boiler  is  lined 
with  brickwork  as  shown  in  Fig.  30.  The  brick  used  for 
the  purpose  should  not  be  porous  but  of  a  porcelain-like 
nature.  The  lower  portion  of  the  interior  surface  of  the 


68  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

boiler  is  furnished  with  a  double-brick  lining,  that  in  the 
upper  portion  being  single.  For  the  sake  of  a  close  joint, 
the  bricks  are  grooved  and  tongued  and  the  spaces  between 
them  filled  with  cement.  Lining  has  to  be  done  with  the 

FIG.  29.  FIG.  30. 


greatest  care,  and  when  testing  the  boiler  in  the  cold  up  to 
six  atmospheres  no  exudation  of  fluid  should  anywhere  be 
perceptible. 

Heating  of  the  mass  in  the  boiler  is  effected  by  four  sys- 
tems of  heating  pipes — see  Fig.  28,  below  to  the  left.  The 
heating  pipes  are  made  of  hard  lead — an  alloy  of  lead  and 
antimony — and  they  have  comparatively  thick  walls — 3.15 
to  3.18  inches.  For  a  boiler  39  feet  long  and  13  feet  in 
diameter,  the  pipes  of  each  heating  system  must  have  a 
length  of  656  feet,  hence  a  total  length  of  2,624  feet  is  re- 
quired. The  heating  pipes  are  connected  with  the  steam 
pipes  and,  on  the  places  where  they  branch  off  from  the 
latter,  are  provided  with  valves  which  prevent  the  lye  from 
running  into  the  boiler  in  case  one  of  the  pipes  becomes 
defective. 

The  proportion  between  wood  and  lye  is  as  follows :  The 
lye  should  have  a  concentration  of  7°  Be.,  and  for  every 
70.62  cubic  feet  of  boiler  space  35.31  cubic  feet  of  pine 
wood,  together  with  the  sawdust  belonging  to  it,  are  used. 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       69 

If  weaker  lyes  are  employed,  the  quantity  of  wood  has  to 
be  correspondingly  decreased  ;  thus,  for  instance,  with  lye 
of  6°,  one-seventh  less  the  quantity  of  wood  is  taken.  The 
wood  and  sawdust  are  as  uniformly  as  possible  distributed 
in  the  boiler,  the  latter  being  filled  one-quarter  full  of 
wood,  and  the  sawdust  is  distributed  in  piles  upon  the  wood. 

When  the  boiler  has  been  filled  with  wood,  the  lids  of 
the  manholes  are  placed  in  position  and  their  joints  luted 
with  a  thick  cellulose  paste.  The  safety-valve  is  then  re- 
lieved and  the  valves  on  the  lower  portion  of  the  boiler  are 
slightly  opened.  Steam  is  then  introduced  into  the  boiler 
in  such  a  way  that  a  very  slight  jet  of  it  passes  out  of  the 
lower  valves,  the  object  of  this  operation  being  to  moisten 
the  wood  uniformly  and  to  expel  the  air  from  its  pores. 
In  working  dry  wood,  the  steam  is  allowed  to  pass  through 
the  boiler  up  to  ten  hours,  but  for  wood  freshly  cut  and 
containing  even  considerable  moisture,  a  much  shorter  time 
is  required.  When,  after  steaming  is  finished,  the  cold  lye 
is  allowed  to  run  into  the  boiler,  the  steam  in  the  pores  of 
the  wood  is  condensed  and  the  lye  penetrates  quickly  into 
the  interior  of  the  blocks  of  wood. 

Immediately  after  the  introduction  of  steam  has  been 
interrupted  and  the  valves  have  been  closed,  the  valve  con-  ^ 
necting  the  boiler  with  the  lye  reservoir  is  opened,  and  in  1 
consequence  of  the  vacuum  thus  created  in  the  boiler  the 
lye  runs  rapidly  into  the  latter.     Steam  is  now  continuously 
introduced  through  the  system  of  heating  pipes,  so  that  the 
contents  of  the  boiler  are  as  rapidly  as  possible  brought  to 
a  temperature  of  230°  F.,   this  temperature  being  main- 
tained as  uniformly  as  possible  for  twelve  hours,  when  it  is 
gradually  raised  to  242.6°  F. 

When  the  temperature  has  reached  230°  F.  a  series  of 
tests  are  made  to  see  how  much  effective  calcium  bisulphite 
is  still  present.  The  test  is  executed  as  follows :  A  glass 
tube  about  7}  inches  long  is  suspended  to  a  vertical  stand 
which  is  furnished  with  marks  indicating  £,  rV,  ^V  of  the 


70  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

volume  content  of  the  glass  tube.  Ammonia  is  now  intro- 
duced into  the  glass  tube  up  to  the  -^  mark,  and  the  tube 
is  then  almost  entirely  filled  with  hot  lye  drawn  from  the 
boiler.  The  glass  tube  is  then  closed  and  ammonia  and  lye 
mixed  by  vigorous  shaking.  The  glass  tube  is  then  sus- 
pended to  the  stand  and  in  a  few  minutes  a  precipitate  is 
formed,  the  semi-fixed  sulphurous  acid  being  neutralized  by 
the  ammonia,  while  calcium  sulphite,  which  is  soluble  with 
difficulty,  is  separated  as  a  precipitate.  From  the  precipi 
tate  the -proportion  of  the  effective  solution  can  be  readily 
determined.  When  the  precipitate  is  only  equal  to  one- 
sixteenth  of  the  length  of  the  glass  tube,  boiling  is  nearly 
complete.  When  the  precipitate  is  only  equal  to  one- 
thirty-second,  heating  is  immediately  interrupted  and  the 
boiler  emptied.  A  very  rapid  decrease  in  the  precipitate 
towards  the  end  of  boiling  is  an  indication  of  detrimental 
processes  taking  place  in  the  boiler.  When  the  lye  in  con- 
sequence of  having  been  improperly  prepared  contains  poly- 
thionic  acids,  a  modification  of  the  process  in  the  boiler 
takes  place,  the  calcium  sulphite  being  then  decomposed 
and  calcium  sulphate  (gypsum)  and  sulphur  are  separated 
upon  the  wood.  The  wood  remains  brown  and  hard,  and 
is  not  completely  converted  into  cellulose. 

When  the  operation  is  properly  conducted,  boiling  is 
finished  in  from  36  to  48  hours. 

For  the  purpose  of  regaining  the  sulphurous  acid,  an 
abundance  of  which  is  still  contained  in  the  lye  after  the 
operation,  the  lye  is  allowed  to  enter  a  lead  coil  which  lies 
in  a  cooling  vat  and  terminates  in  one  of  the  towers.  In 
the  lead  coil  the  water  which  is  saturated  with  sulphurous 
acid  is  condensed  and  collected  by  itself,  while  the  sulphur- 
ous acid  passes  into  the  tower,  to  be  again  used  for  the 
preparation  of  lye. 

WASHING    THE    CELLULOSE. 

When   boiling    has   been  finished,   the  contents  of  the 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       71 

boiler  are  emptied  into  a  receptacle  underneath  the  boiler, 
and  after  the  cellulose-mass  has  settled  to  the  bottom,  the 
supernatant  fluid  is  discharged  into  a  watercourse,  provided 
it  is  in  a  highly  diluted  state.  If  this,  however,  is  not  the 
case,  the  fluid  has  to  be  mixed  with  a  quantity  of  milk  of 
lime  sufficient  for  the  conversion  of  the  calcium  bisulphite 
and  the  free  sulphurous  acid  still  contained  in  it,  into  cal- 
cium sulphite,  which  settles  on  the  bottom  of  the  receptacle 
and  may  be  again  converted  into  calcium  bisulphite  by  the 
introduction  of  sulphurous  acid  into  the  water  poured 
over  it. 

When  the  boiler  has  been  emptied  it  is  rinsed  out  with 
water,  and  before  starting  a  fresh  operation,  it  is  advisable 
to  subject  it  to  a  thorough  examination  and  to  knock  off 
with  a  wooden  mallet  any  gypsum  which  may  have  de- 
posited on  the  brick  work. 

The  cellulose-mass  coming  from  the  boiler  contains  cer- 
tain quantities  of  finely  divided  gypsum,  fragments  of 
neutral  calcium  sulphite,  and  besides  is  saturated  with  lye. 
To  free  it  from  these  admixtures  it  is  subjected  to  the  action 
of  a  stamping  mill,  the  operation  being  assisted  by  large 
quantities  of  water.  The  cellulose-mass  is  directly  con- 
veyed by  a  transporting  contrivance  from  the  boiler  to  a 
funnel  from  which  it  falls  into  the  stamping  trough,  in 
which,  mixed  with  the  proper  quantity  of  water,  it  is  sub- 
jected to  the  action  of  the  stamps.  The  latter  are  so  set 
that  they  cannot  fall  entirely  to  the  bottom  of  the  trough, 
crushing  the  mass  being  thus  prevented.  From  the  stamp- 
ing mill  the  pasty  mass  runs  off  through  broad  gutters 
which  are  provided  with  sand-catchers  for  keeping  back 
sand,  grains  of  gypsum,  etc.,  the  particles  floating  on  the 
top  being  retained  by  a  cleaner  placed  over  the  fluid. 
From  the  gutters  the  pulp  reaches  an  inclined  cylinder 
covered  with  a  wire  sieve.  The  water  runs  off  through  the 
meshes  of  the  sieve,  while  the  cellulose  in  the  form  of 
crumbs  leaves  the  cylinder  at  the  lower  end  and  is  quite 
completely  freed  from  moisture  by  rolls. 


72  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

DEFECTS    OF  CELLULOSE    AND  THEIR  REMOVAL. 

Owing  to  deviations  from  the  proper  process  of  working, 
the  finished  cellulose  may  show  various  defects  which  may 
partially  be  remedied.  According  to  Mitscherlich  the 
most  important  defects  are  as  follows : 

The  cellulose  instead  of  being  pure  white  shows  a  yellow- 
ish or  brownish  color.  The  cause  of  this  phenomenon  is 
due  to  the  fact  that  towards  the  end  of  boiling  the  required 
quantity  of  sodium  bisulphite  was  no  longer  present.  Such 
cellulose  can  be  made  quite  white  by  bleaching  with  chlorine. 

Some  white  pieces  not  converted  into  fibre  may  occur  in 
the  otherwise  uniform  mass,  which  is  an  indication  of  too 
much  wood  having  been  brought  into  the  boiler.  Such 
cellulose  may  very  well  be  used  for  the  manufacture  of  firm 
and  strong  paper,  but  must  first  be  carefully  rolled.  How- 
ever, such  cellulose  is  less  suitable  for  bleaching. 

The  occurrence  of  black  particles  in  the  mass  is  gen- 
erally due  to  insufficient  cleaning  of  the  wood  before  it  is 
cut  up,  and  is  caused  by  rotten  pieces  of  bark  which  have 
been  left  on  the  wood.  The  black  spots  may  also  be  due  to 
particles  of  the  belts,  this  being  a  defect  which  cannot  be 
removed.  Some  kinds  of  cellulose  contain  small,  soft 
bundles  of  fibre  of  a  brownish  color  which  may  have  been 
caused  by  the  respective  particles  having  become  too  hot  in 
the  boiler,  or  by  incompletely  freeing  the  wood  from  bast. 
These  defects,  as  a  rule,  disappear  completely  by  subjecting 
the  cellulose  to  bleaching  with  chlorine. 

The  occurrence  of  larger  brown  bundles  of  fibre  of  con- 
siderable firmness  is  mostly  due  to  a  gross  error  committed 
in  boiling,  or  to  the  fact  that  some  of  the  stamps  of  the 
stamping-mill  have  come  too  near  to  the  trough.  With  the 
use  of  the  proper  quantity  of  water  and  a  right  width  of  the 
slits  in  the  splinter-catcher,  these  pieces  should  have  been 
retained  during  washing. 

With  the  microscope  small,  lustrous  crystals  may  some- 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       73 

times  be  noticed  in  the  cellulose,  this  being  proof  of  an  in- 
sufficient quantity  of  water  having  been  used  in  washing. 

If  the  microscope  shows  the  presence  of  small  particles  of 
an  earthy  appearance  it  is  an  indication  of  too  little  wood 
having  been  used  in  boiling,  these  particles  consisting  of 
neutral  calcium  sulphite.  They  can  be  most  readily  re- 
moved by  an  addition  of  hydrochloric  acid  to  the  wash- 
water,  but  cellulose  thus  treated  requires  a  larger  quantity 
of  chlorine  in  bleaching.  A  change  in  color  of  the  at  first 
pure-white  cellulose  during  washing  is  due  to  small  quanti- 
ties of  iron  which  reach  the  mass  chiefly  through  the  wash- 
water  and  iron  utensils.  This  iron  may  also  be  removed 
by  acidulating  the  wash-water  with  hydrochloric  acid. 

The  finished  cellulose  may  either  be  immediately  used 
for  the  manufacture  of  paper,  or  it  may  be  freed  from  the 
larger  portion  of  water  by  pressure.  If,  however,  it  is  to 
be  kept  without  undergoing  a  change,  it  has  to  be  com- 
pletely dried,  as  otherwise  it  becomes  readily  mildewed, 
especially  when  exposed  to  heat. 

Other  methods  for  the  manufacture  of  cellulose  by  the 
sulphite  process  differ  in  details  only  from  Mitscherlich's 
process  above  described,  all  being  based  upon  the  proposi- 
tion that  by  boiling  wood  under  an  increased  pressure  with 
solution  of  calcium  bisulphite  the  encrusting  substance  is 
dissolved  and  the  mass  need  only  be  thoroughly  washed  to 
yield  a  material  available  for  the  manufacture  of  paper. 

PREPARATION    OF    CELLULOSE    WITH   THE  ASSISTANCE    OF  THE 
ELECTRIC  CURRENT. KELLNER'S  PROCESS. 

This  process  differs  essentially  from  the  methods  pre- 
viously described,  and  is  based  upon  a  very  ingenious  ap- 
plication of  the  electric  current,  the  latter  being  used  for 
decomposing  common  salt  solution.  When  an  electric  cur- 
rent of  suitable  strength  is  allowed  to  act  upon  a  solution  of 
sodium  chloride  (common  salt),  caustic  soda,  free  chlorine 


74  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

and  hypochlorous  acid  are  formed.  By  allowing  these 
bodies  to  act  alternately  at  a  suitable  temperature  upon 
wood,  the  lignin  will  in  a  certain  time  be  completely  de- 
stroyed and  pure  cellulose  remain  behind. 

For  carrying  out  his  process,  Kellner  uses  the  apparatus, 
shown  in  Fig.  31,  consisting  of  three  boiling  vessels  B,  A 
and  L,  which  are  connected  one  with  the  other  by  the  pipes 
H,  J,  M,  TV  and  K,  the  positive  pole  of  a  source  of  electricity 


(a  dynamo)  entering  at  R  and  the  negative  pole  at  S.  When 
the  apparatus  is  to  be  used,  the  boilers  A  and  B  are  charged 
through  the  manholes  E  with  wood  prepared  in  the  usual 
manner,  and  common  salt  solution  is  then  allowed  to  run  in 
until  it  becomes  visible  in  the  fluid-indicator  L  which  is 
located  in  the  intermediary  boiler.  Coils  of  pipe  through 
which  high-pressure  steam  is  conducted  lie  in  the  boilers 
A  and  B.  Heating  is  continued  until  the  temperature  of 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       75 

the  common  salt  solution  has  been  brought  to  262.4°  F./ 
when  the  electric  current  is  closed,  whereby  the  common 
salt  solution  is  decomposed,  caustic  soda,  free  chlorine  and 
hypochjorous  acid  being  formed.  The  fluids  containing 
these  bodies  ascend  from  M  and  N  through  J  J,  act  upon 
the  wood  contained  in  A  and  B,  and  reunite  in  the  vessel 
L.  The  gases  accumulating  in  L  are  conducted  through 
the  valve  V  and  the  pipe  T  into  the  condenser  P. 

As  will  be  seen  from  the  above  description,  the  wood  in 
one  of  the  boilers  is  treated  with  caustic  soda  lye  and  that 
in  the  other  with  chlorine  and  hypochlorous  acid,  both  of 
these  bodies  having  a  destructive  effect  upon  the  encrusting 
substance.  To  make  the  process  entirely  uniform,  the 
direction  of  the  electric  current  is  from  time  to  time  re- 
versed, so  that  the  wood  which  has  been  treated  with 
caustic  soda  is  exposed  to  the  action  of  the  chlorine  and 
vice  versa. 

By  reason  of  the  powerful  chemical  action  of  the  caustic 
soda  and  chlorine  alternately  exerted  at  short  intervals 
upon  the  wood,  the  operation  proceeds  with  greater  rapidity 
and  smoothness  than  by  any  other  method,  and  cellulose  in 
a  perfectly  bleached  state  is  directly  obtained  from  the 
apparatus.  These  advantages  should  certainly  be  sufficient 
to  insure  to  Kellner's  process  extended  application  in  prac- 
tice. 

PREPARATION  OF  CELLULOSE  FROM  STRAW. 

While  all  efforts  to  prepare  from  the  straw  of  our  varieties 
of  grain  a  cellulose  suitable  for  the  manufacture  of  finer 
qualities  of  paper  were  for  a  long  time  in  vain,  recent  en- 
deavors in  this  direction  have  been  crowned  with  success, 
and  this  material  is  now  worked  on  a  large  scale  by  several 
factories.  In  working  straw  for  cellulose,  the  preparatory 
operations  form  a  very  important  part  of  the  process.  The 
straw  has  not  only  to  be  freed  from  adhering  earth,  weeds, 
etc.,  but  also  as  far  as  possible  from  the  knots  of  the  indi- 


76  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

vidual  stalks,  these  knots  offering  far  greater  resistance  to 
the  action  of  the  chemicals  than  the  tubular  portions. 

The  operation  is  commenced  by  opening  the  bundles  of 
straw  and  shaking  out  the  weeds  as  much  as  possible.  The 
straw  is  then  cut  very  fine  in  a  straw-cutter  and  cleaned  by 
means  of  a  fan.  The  current  of  air  in  the  latter  should  be 
of  such  a  force  that  the  particles  of  stalks  are  positively 
carried  away,  while  the  heavier  bodies,  including  the  knot- 
pieces,  fall  to  the  bottom.  If  the  operation  is  properly 
carried  on,  the  greater  portion  of  the  knot-pieces,  as  well 
as  the  grain  still  contained  in  the  straw,  will  be  found  in 
the  mass  collected  in  front  of  the  fan,  while  the  cut  straw 
which  has  been  blown  away  consists  chiefly  only  of  tubular 
particles  of  stalks. 

For  the  further  working  of  the  winnowed  straw  the  soda 
process  is  generally  used,  the  encrusting  substance  of  the 
straw  being  much  more  readily  dissolved  in  the  alkaline 
fluid  than  that  of  wood.  Hence,  boiling  may  be  effected 
under  considerably  less  pressure,  three  to,  at  the  utmost 
five,  atmospheres  being  in  most  cases  sufficient. 

The  great  volume  occupied  by  the  finely-cut  straw  is  an 
objectionable  feature  which  might  necessitate  the  employ- 
ment of  boilers  of  very  large  dimensions.  This  may,  how- 
ever, be  overcome  by  pressing  down  the  straw  in  the  boiler, 
while  the  lye  is  allowed  to  enter  from  below.  By  the  action 
of  the  lye  the  bulk  of  the  straw  is  very  rapidly  decreased 
and  1,100  pounds  of  straw  can  in  this  manner  be  readily 
worked  at  one  time. 

Horizontal  cylindrical  boilers  of  the  revolving  type  have 
been  found  most  suitable  for  working  straw.  The  boiler 
having  in  the  above-mentioned  manner  been  filled  with 
straw  and  lye,  a  portion  of  the  latter  is  discharged,  so  that 
the  boiler  is  only  one-third  full  of  lye.  Steam  is  then  in- 
troduced through  the  hollow  trunnions  of  the  boiler  and 
the  latter  is  made  to  revolve  slowly — once  in  one  or  two 
minutes — around  its  axis.  By  boiling,  the  straw  is  con- 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       77 

verted  into  a  pasty  mass,  and  boiling  has  to  be  continued 
until  samples  taken  from  the  boiler  show  the  complete  dis- 
integration of  the  knotty  particles. 

The  boiler  is  then  placed  so  that  the  man-hole  is  turned 
downward,  and  the  pasty  contents  are  allowed  to  run  out. 
Since  the  individual  particles  adhere  together  in  the  form 
of  fibres,  the  entire  mass  is  passed  through  a  stuff-mill 
consisting  of  a  stationary  bed-stone  and  a  revolving  runner. 

Since  the  characteristic  yellow  coloring-matter  of  the 
straw  is  not  decomposed  by  boiling  with  the  alkali,  the  re- 
sulting cellulose  would  also  be  of  a  yellow  color,  and  hence 
the  mass  has  to  be  bleached.  Before  this  is  done,  it  must, 
however,  be  completely  freed  from  alkali  by  washing, 
special  apparatus  being  employed  for  this  purpose. 

Bleaching  by  means  of  chloride  of  lime  is  effected  in  the 
hollander,  11  to  22  pounds  of  chloride  of  lime  being  re- 
quired for  every  220  pounds  of  dry  straw.  During  the 
process  of  bleaching,  the  mass  must  be  kept  in  constant 
motion,  and  the  operation  should  be  effected  at  the  ordinary 
temperature,  since  at  an  increased  heat,  the  cellulose  itself 
would  be  attacked  by  the  chlorine  and  carbonic  acid  be 
evolved  from  the  mass.  The  treatment  with  chloride  of 
lime  must  be  succeeded  by  thorough  washing  and,  in  case 
the  finished  product  is  not  to  be  immediately  used  for  the 
manufacture  of  paper,  it  has  to  be  freed  from  water  by 
hydraulic  presses. 

According  to  different  statements,  the  yield  of  finished 
cellulose  varies  very  much,  but  it  appears  to  be  chiefly  de- 
pendent on  the  state  of  maturity  of  the  straw  used.  From 
all  that  can  be  learned  on  the  subject,  a  yield  of  72.6  to  88 
pounds  of  dry  cellulose  from  every  220  pounds  of  straw  used 
may  be  calculated  on. 

Besides  the  straw  of  the  different  varieties  of  grain,  other 
parts  of  plants  are  utilized  for  the  preparation  of  cellulose 
for  the  manufacture  of  paper,  esparto  (from  Stipa  tenacissima) 
especially  being  largely  employed  in  England  for  that 


78  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

purpose.  The  leaves  of  the  esparto  plant  present  the  ad- 
vantage of  being  very  readily  disintegrated,  an  increase  in 
the  pressure  during  boiling  not  even  appearing  necessary. 
The  cellulose  obtained  from  esparto  is  said  to  be  distin- 
guished by  great  firmness  and  pliability,  so  that  it  is  suit- 
able for  the  manufacture  of  very  firm,  white  writing-papers. 
The  quantitative  yield  also  is  said  to  be  very  satisfactory, 
92.4  to  110  pounds  of  cellulose  being  obtained  from  220 
pounds  of  raw  material. 

Jute  bagging,  which  has  been  used  for  shipping  trans- 
atlantic products,  is  also  utilized,  when  it  can  be  had  in 
sufficient  quantities,  for  the  preparation  of  cellulose,  and 
this  cellulose  is  especially  suitable  for  the  imitation  of  gen- 
uine Manila  paper  which  is  prepared  from  the  fibres  of 
Manila  hemp,  Musa  textilis.  The  first  step  in  working  jute 
in  the  form  of  cuttings  or  "  butts,"  spinner's  waste  and 
bagging,  is  to  cut  up  the  material  in  a  rag-cutting  machine. 
The  comminuted  mass  is  then  brought  into  a  rag-boiler 
and  for  some  time  boiled  under  slight  pressure — 1J  atmos- 
pheres— with  a  comparatively  large  quantity  of  lime — 
25  to  35  per  cent,  of  the  weight  of  the  jute.  It  is  then 
washed  in  a  half-stuff  hollander  and  ground.  As  a  rule,  it 
is  finally  slightly  bleached  with  chloride  of  lime. 

UTILIZATION    OF    EXHAUSTED    LYES    AND    THEIR 
NEUTRALIZATION. 

The  fluids  which  have  served  for  the  preparation  of 
cellulose  from  wood  contain,  in  addition  to  a  consider- 
able quantity  of  organic  substance,  the  total  quantity  of 
mineral  substances  employed  in  their  preparation.  Partly 
for  economic,  and  partly  for  hygienic,  reasons,  these  sub- 
stances have  either  to  be  reconverted  into  such  products  as 
can  be  again  utilized  in  succeeding  operations,  or  it  must 
be  endeavored  to  change  them  in  such  a  manner  that  they 
may,  without  risk,  be  discharged  into  a  natural  water- 
course, river  or  creek. 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       79 

When  working  with  the  soda  process,  efforts  are  generally 
made  to  recover  the  soda  as  far  as  possible.  The  exhausted 
lyes  contain  the  soda  largely  in  the  form  of  organic  com- 
binations which  can  be  broken  up  by  heat,  carbonate  of 
soda  remaining  finally  behind,  which  may  be  again  used 
for  the  preparation  of  lye.  In  order  to  recover  the  soda, 
the  exhausted  lyes  are  evaporated  to  dryness,  and  the  re- 
sulting solid  mass  is  calcined  under  the  access  of  a  strong 
current  of  air.  The  organic  substance  is  thereby  completely 
destroyed,  the  residue  consisting  of  calcined  (anhydrous) 
soda. 

Since  the  evaporation  of  such  large  quantities  of  fluid  as 
result  in  the  manufacture  of  cellulose,  requires  a  consider- 
able amount  of  fuel,  the  apparatus  used  for  the  purpose 
should  be  so  constructed  as  to  allow  of  the  heat  produced 
being  utilized  to  the  fullest  extent.  Numerous  propositions 
having  more  or  less  the  object  in  view,  namely,  the  saving 
of  fuel,  have  from  time  to  time  been  made.  However, 
reverberatory  furnaces  are  most  frequently  used  for  calcining 
the  evaporated  mass,  the  still  very  hot  fire  gases  escaping 
from  the  furnace  being  utilized  for  heating  shallow  pans 
in  which  the  lyes  are  constantly  more  and  more  concen- 
trated, and  finally  converted  into  a  solid  mass  ready  for 
calcination  in  the  furnace. 

The  quantity  of  soda  recovered  is  of  course  considerably 
smaller  than  that  originally  used,  a  portion  of  it  having 
been  lost  in  the  wash  waters,  but  the  latter  do  not  contain 
enough  of  it  to  make  their  evaporation  profitable.  How- 
ever, if  the  operation  is  properly  conducted,  from  60  to  66 
per  cent,  of  the  soda  used  may  be  recovered.  When  work- 
ing with  the  sulphite  process,  it  is  of  the  utmost  importance 
to  change  the  lyes  so  as  to  be  able  to  discharge  them,  with- 
out risk,  into  running  water.  According  to  Mitscherlich, 
this  is  to  be  effected  by  greatly  diluting  the  lyes,  as  well  as 
the  water  used  in  washing  the  cellulose.  However,  it  must 
be  borne  in  mind  that  very  large  quantities  of  exhausted 


80  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

lye  are  daily  produced  in  a  cellulose  plant.  Every  quart 
of  exhausted  sulphite  lye  contains,  in  round  numbers,  3 
ounces  of  organic  substance  in  solution  and,  in  addition, 
the  total  quantity  of  mineral  substances  contained  in  the 
original  lye. 

However,  since  the  lyes  contain  considerable  quantities 
of  sulphites  which  become  decomposed  in  water,  sulphur- 
etted hydrogen  being  evolved,  it  will  be  readily  understood 
that  the  waters  of  even  a  quite  considerable  stream  will,  in 
the  course  of  time,  become  polluted  to  such  an  extent  as  to 
kill  the  fish  inhabiting  them,  sulphuretted  hydrogen  being 
an  exceedingly  violent  poison  for  them. 

It  would,  therefore,  seem  absolutely  necessary  to  neutral- 
ize the  lyes  as  much  as  possible  before  discharging  them 
into  a  water-course.  According  to  a  process  proposed  for 
this  purpose  by  A.  Frank,  the  exhausted  lye  from  a  boiling 
is  mixed  in  a  large  cistern  with  a  sufficient  quantity  of 
milk  of  lime  to  form  neutral  calcium  sulphite  which,  being  a 
salt  that  dissolves  with  difficulty,  settles  to  the  bottom,  and 
after  having  been  freed  as  far  as  possible  from  the  fluid  in 
a  filter-press,  can  be  re-used  for  the  preparation  of  sulphite 
lye.  The  fluid  having  been  separated  from  the  neutral 
calcium  sulphite  is  freed  in  another  receptacle  from  the  ex- 
cess of  lime  by  the  introduction  of  smoke  gases  containing 
much  carbonic  acid,  while  the  oxidation  of  a  considerable 
quantity  of  organic  substance  is  effected  by  conducting 
compressed  air  through  the  fluid.  The  fluid  thus  far  puri- 
fied is  conducted  upon  an  irrigation  field  and,  after  re- 
maining there  for  some  time,  is  discharged  into  running 
water.  The  calcium  sulphite  thus  regained  covers  a  con- 
siderable portion  of  the  expense  incurred  in  carrying  out 
the  process. 

The  sulphite  lyes  may  also  be  utilized  in  tanning,  but 
being  of  a  very  dark  color,  they  impart  this  color  to  the 
leather,  and  besides  make  it  brittle.  However,  this  draw- 
back may  be  overcome,  and,  according  to  a  process  proposed 


CELLULOSE    FROM    WOOD,  OR    CHEMICAL    WOOD-PULP.       81 

by  Honig,  the  lye,  previous  to  being  concentrated  by  evap- 
oration, is  deprived  of  its  color  by  treating  it  with  zinc 
dust  and  sulphuric  acid,  a  sufficient  quantity  of  the  latter 
to  decompose  all  the  sulphites  contained  in  the  fluid  being 
required. 

In  carrying  out  this  process,  the  resulting  large  quanti- 
ties of  sulphurous  acid  may,  of  course,  be  utilized  for  the 
preparation  of  fresh  lye,  a  portion  of  the  expense  incurred 
being  thereby  covered. 
6 


IV. 

VEGETABLE  PARCHMENT. 

WHEN  unsized  paper,  which  should,  however,  contain  no 
wood-pulp,  is  for  a  short  time  subjected  to  the  action  of 
quite  concentrated  sulphuric  acid,  the  cellulose  undergoes 
a  peculiar  physical  change.  The  paper  loses  considerably 
in  thickness,  assumes  a  transparent  appearance,  becomes 
harder  and  acquires  a  condition  reminding  one  of  horn,  be- 
coming at  the  same  time  about  five  times  as  tenacious  as 
the  original  material.  When  paper  thus  treated  is  moist- 
ened, it  loses  its  rigidity  and  acquires  the  condition  of 
animal  bladder.  If  stretched  tight  and  allowed  to  dry,  it 
regains  its  former  horn-like  condition.  The  chemical  com- 
position of  vegetable  parchment  is  exactly  the  same  as  that 
of  cellulose  and,  hence,  the  change  effected  by  parchment- 
izing  in  the  above-described  manner  is  simply  a  physical 
one.  Concentrated  solution  of  zinc  chloride  produces  the 
same  parchmentizing  effect  as  sulphuric  acid,  but  in  prac- 
tice this  process  is  not  used,  because  it  is  far  more  expensive, 
and  the  complete  removal  of  the  poisonous  zinc  salt  is  far 
more  troublesome  than  that  of  sulphuric  acid. 

The  parchmentizing  action  of  sulphuric  acid  is  explained 
as  follows  :  A  solution  of  cellulose  in  concentrated  sulphuric 
acid  is  first  formed  to  a  certain  depth  upon  the  surface  of 
the  paper,  but  so  soon  as  the  latter  is  taken  from  the  sul- 
phuric acid  and  brought  in  contact  with  a  large  quantity 
of  water,  the  solution  is  immediately  decomposed  to  free 
sulphuric  acid  and  amyloid,  the  latter  cementing  the  indi- 
vidual cellulose  fibres  together  to  a  uniform  mass.  By  this 

(82) 


VEGETABLE    PARCHMENT.  83 

cementation  the  paper  acquires  its  extraordinary  strength 
and  transparent  appearance. 

NATURE  OF  THE  PAPER  TO  BE  PARCHMENTIZED. 

For  the  production  of  vegetable  parchment  of  the  proper 
quality,  paper  especially  made  for  this  purpose  has  to  be 
used,  it  being  of  the  utmost  importance  that  it  should  not 
contain  a  filling  stuff  of  any  kind,  and  that  it  consists  of 
nothing  else  but  cellulose.  It  must,  therefore,  neither  be 
sized  nor  contain  an  addition  of  a  foreign  body. 

In  manufacturing  paper  intended  for  parchmentizing  it 
has  to  be  taken  into  consideration  that  its  bulk  is  consider- 
ably decreased  by  the  process,  and  hence  it  has  to  be  made 
of  sufficient  thickness.  To  make  the  process  of  parchment- 
izing effectual,  it  is  necessary  for  the  paper  to  become  com- 
pletely impregnated  with  the  acid  the  moment  it  comes  in 
contact  with  it,  it  being  only  under  these  conditions  that 
the  momentary  solution  of  the  cellulose  in  the  sulphuric 
acid  takes  place,  not  only  upon  the  surface,  but  also  through- 
out the  entire  bulk,  of  the  paper.  Hence  paper  to  answer 
these  requirements  must,  on  the  one  hand,  be  of  suitable 
thickness,  and,  on  the  other,  should  not  be  subjected  to 
great  pressure  in  passing  through  between  the  rolls.  In 
this  manner  a  loose,  spongy  paper  is  obtained,  which  is  of 
comparatively  little  value  for  other  purposes,  but  by  reason 
of  its  porous,  felt-like  nature  is  especially  well  adapted  for 
the  preparation  of  vegetable  parchment. 

As  previously  mentioned,  by  bringing  paper  in  contact 
with  sulphuric  acid  an  actual  solution  of  cellulose  in  the 
acid  takes  place,  which  must,  however,  be  again  rapidly 
decomposed.  This  fact  renders  it  impossible  to  impregnate 
the  paper  throughout  its  entire  bulk  when  the  latter  exceeds 
a  certain  limit,  because  before  the  acid  could  penetrate  into 
the  interior,  a  comparatively  thick  layer  on  the  surface 
would  be  completely  dissolved.  However,  if  parchment  of 
greater  thickness  is  to  be  prepared,  recourse  may  be  had  to 


84  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

a  process  which  is  based  upon  the  fact  that  paper  just  parch- 
mentized  is  very  sticky  when  taken  from  the  sulphuric  acid 
bath.  Two,  three,  or  even  four,  breadths  of  paper  are 
simultaneously  subjected — each  by  itself — to  the  action  of 
the  sulphuric  acid,  and  when  taken  from  the  latter  are 
passed  together — one  on  top  of  the  other — between  rolls, 
whereby,  on  the  one  hand,  a  considerable  portion  of  adher- 
ing acid  is  squeezed  out,  and,  on  the  other,  the  breadths  of 
paper  are  inseparably  cemented  together. 

SULPHURIC    ACID    USED    FOR    PARCHMEXTIZING. 

In  order  to  obtain  parchment  of  always  the  same  quality, 
sulphuric  acid  of  the  same  concentration  and  temperature 
has  to  be  employed,  and  allowed  to  act  upon  the  paper  for 
a  certain  time.  While  the  first-mentioned  factors  can  be 
readily  ascertained,  the  time  during  which  the  acid  has  to 
act  depends  largely  on  practical  experience,  and  has  to  be 
fixed  for  every  kind  of  paper  by  a  few  experiments  on  a 
small  scale.  Sulphuric  acid  of  a  specific  gravity  between 
1.659  (58°  Be.)  and  1.754  (63°  Be.)  has,  after  many  experi- 
ments, proved  most  suitable  for  use.  Larger  quantities  of 
a  fluid  of  the  desired  concentration  are  at  one  time  prepared 
by  mixing  concentrated  sulphuric  acid  with  water,  the 
mixture  being  allowed  to  stand  by  itself  until  its  temper- 
ature is  reduced  to  at  least  60°  F.,  because  acid  of  a  higher 
temperature  acts  too  energetically  upon  the  paper,  and  the 
latter  might  in  consequence  be  readily  converted  into  a 
slimy  mass.  Many  manufacturers  prefer  even  to  work  with 
acid  of  quite  a  low  temperature  because  all  the  operations 
can  then  be  carried  on  more  leisurely. 

The  mixing  of  larger  quantities  of  sulphuric  acid  with 
water  being  disagreeable  work  requiring  great  precaution, 
most  of  the  manufacturers  of  parchment  paper  work  with  so- 
called  chamber  acid,  which  has  a  specific  gravity  in  round 
numbers  of  60°  B£.,  and  can  be  directly  used,  besides  being 
considerably  cheaper  than  highly  concentrated  sulphuric 
acid. 


VEGETABLE    PARCHMENT.  85 

When  working  with  acid  of  60°  Be'.,  at  a  temperature 
not  exceeding  60°  F.,  five  seconds'  contact  with  the  acid 
suffice  for  parchmentizing  thinner  varieties  of  paper. 
Thicker  papers  require  a  correspondingly  longer  time,  and 
very  thick  papers  are  passed  through  the  acid  reservoir  so 
slowly  as  to  remain  submerged  upwards  of  20  seconds. 

It  must,  however,  be  borne  in  mind  that  by  coming  in 
contact  with  the  paper,  the  acid  in  the  parchmentizing  ves- 
sel becomes  slightly  heated,  and  hence  to  prevent  it  from 
acting  too  energetically  upon  the  paper,  the  velocity  with 
which  the  latter  is  drawn  through  the  acid  has  to  be  some- 
what increased  after  the  operation  has  for  a  short  time  been 
in  progress. 

When  the  paper  has  remained  the  required  time  in  the 
acid  it  is  as  rapidly  as  possible  withdrawn  from  the  action 
of  the  latter,  this  being  effected  by  bringing  it  in  contact 
with  large  quantities  of  water,  by  which  the  acid  is  diluted 
to  such  an  extent  that  the  cellulose  is  no  longer  affected  by 
it.  The  last  remnants  of  sulphuric  acid  adhering  to  the 
parchment  are  removed  by  treatment  with  an  alkaline  fluid. 

PARCHMENTIZING    APPARATUS. 

For  the  manufacture  of  parchment  paper  on  a  large  scale, 
an  apparatus  is  used,  the  essential  features  of  which  are  as 
follows :  The  endless  paper  to  be  worked  is  wound  on  a  roll 
from  which  it  can  be  smoothly  unrolled  under  a  slight  pull, 
and  is  next  carried  under  glass  rolls  beneath  the  surface  of 
the  sulphuric  acid,  the  latter  being  contained  in  a  lead- 
lined  trough.  By  arranging  several  rolls  in  the  trough  the 
paper  is  for  a  suitable  time  exposed  to  action  of  the  acid, 
and  is  finally  lifted  from  it  in  a  perpendicular  direction. 
As  soon  as  it  appears  above  the  level  of  the  fluid  it  is  car- 
ried through  between  two  rolls  with  sufficient  pressure  for 
the  greater  portion  of  acid  to  fall  back  into  the  lead-lined 
trough.  The  paper  is  now  carried  over  glass  rolls  into  a 
long  trough  filled  with  clean  water,  in  which  the  greater 


86  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

portion  of  still  adhering  acid  is  rinsed  off.  Since  this  first 
wash  water  becomes  highly  heated,  it  is  advisable  to  charge 
the  trough  at  the  start  with  very  cold  water.  From  the  first 
trough  the  paper  reaches  another  one,  in  which  it  is  further 
treated  with  water,  it  being  best  to  have  the  water  in  this 
trough  constantly  running  in  a  direction  counter  to  that  of 
the  paper.  This  water  absorbs  but  a  very  small  quantity  of 
sulphuric  acid  from  the  paper,  and  is  allowed  to  run  off 
from  the  wash-trough.  It  is  advisable  to  sprinkle  both 
sides  of  the  paper,  as  it  rises  from  the  second  trough,  with 
fine  jets  of  water  from  two  horizontal  pipes. 

The  last  traces  of  acid  still  adhering  to  the  paper  are 
removed  by  passing  it  through  a  trough  filled  with  water, 
which  is  constantly  kept  alkaline  by  small  quantities  of 
caustic  soda  lye  or  ammonia.  After  again  being  treated 
with  clean  water  the  paper  is  subjected  to  strong  pressure 
between  rubber  rolls  or  wooden  rolls  covered  with  felt.  It 
then  passes  between  adjusting  rolls,  and  finally  reaches 
hollow  iron  rolls  heated  by  steam  for  the  purpose  of  drying 
the  finished  parchment. 

While  drying,  the  parchment  has  to  be  subjected  to  strong 
tension  both  lengthways  and  laterally,  otherwise  it  would 
contract  very  much  and  acquire  an  uneven  and  wrinkled 
surface. 

Since  the  sulphuric  acid  used  in  the  preparation  of 
parchment  is  only  highly  diluted,  without  being  otherwise 
changed,  provision  should  be  made  for  its  recovery.  This 
can  best  be  effected  by  having  the  first  wash-trough  into 
which  the  paper  passes  directly  from  the  sulphuric  acid  vat, 
of  but  a  small  size  and  furnishing  it  with  a  large  discharge 
valve,  as  well  as  with  quite  a  large  water-supply  pipe. 
Two  horizontal  sprinkling  pipes  are  also  fixed  over  this 
trough. 

When  the  content  of  acid  in  the  first  wash  water  has 
increased  to  such  an  extent  as  to  amount  to  20  per  cent,  of 
the  entire  quantity  of  fluid,  the  discharge  valve  and  the 


VEGETABLE    PARCHMENT.  87 

sprinkling  pipes  are  opened.  The  contents  of  the  trough 
run  off  in  a  few  seconds,  the  acid  being  during  this  time 
washed  from  the  paper  by  the  sprinkling  pipes.  When  the 
trough  is  empty,  the  discharge  valve  is  immediately  closed 
and  the  trough  refilled  with  water  by  opening  the  cock  of 
the  large  water  pipe,  the  sprinkling  pipes  being  finally 
closed.  With  a  small-sized  trough,  a  large  valve,  and  a 
water  pipe  of  considerable  diameter,  the  discharge  of  the 
very  acid  water,  as  well  as  the  refilling  of  the  trough  is  so 
rapidly  effected  that  the  supply  of  water  furnished  during 
this  time  by  the  action  of  the  sprinkling  pipes  is  sufficient 
and  the  operation  need  not  be  stopped,  and  thus  very 
large  rolls  of  endless  paper  can,  without  interruption,  be 
made  into  parchment. 

The  wash  water  from  the  first  trough  when  it  contains 
about  20  per  cent,  of  sulphuric  acid,  can  be  readily  worked 
to  sulphuric  acid  of  60°  Ed,  it  being  only  necessary  to 
evaporate  it  in  a  shallow  lead  pan  heated  by  steam  till  the 
acid  has  acquired  its  ordinary  concentration.  When  work- 
ing with  the  more  concentrated  commercial  sulphuric  acid, 
the  wash  water  is  utilized  in  place  of  pure  water,  for  dilut- 
ing the  acid.  However,  as  in  this  case,  an  excess  of  sul- 
phuric acid  would  before  long  accumulate  in  the  factory,  it 
is  advisable  to  use,  instead  of  ordinary  commercial  acid, 
fuming  sulphuric  acid,  the  latter  by  reason  of  its  content  of 
sulphur  trioxide  requiring  much  more  water  for  dilution  to 
60°  B<1 

PROPERTIES    OF    PARCHMENT    PAPER. 

By  the  conversion  of  ordinary  paper  into  parchment  its 
bulk  is  considerably  decreased  as  well  as  its  content  of  ash, 
but  its  specific  gravity  is  much  increased.  The  principal 
feature,  however,  is  the  increase  in  absolute  strength,  which 
makes  parchment  especially  suitable  for  book  bindings  and 
all  other  purposes  for  which  strength  is  a  requisite.  The 
changes  paper  undergoes  by  parchmentizing  are  shown  for 
three  different  varieties  of  it,  in  the  table  below  : 


88 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


Thickness 
milli- 
meters. 

Specific 
gravity. 

Absolute 
strength 
per  square 
millimeter 
Kilogrammes. 

Content  of 
moisture 
per  cent. 

Content 
of  ash. 

Raw  paper  .    .    . 
Parchment  paper. 

0.234 
0.152 

0.617 
0.964 

1.415 

6.436 

6.785 
8.778 

0633 
0.496 

Raw  paper  . 
Parchment  paper. 

0.178 
0.113 

0.543 
0.937 

1.483 
5.111 

7071 
8.483 

0.645 
0.458 

Raw  paper  .    .    . 
Parchment  paper. 

0.134 
0.083 

0.624 
0.927 

1.503 

5.777 

6.978 
9.160 

0.678 
0.559 

As  previously  mentioned,  the  preparation  of  parchment 
of  special  thickness  presents  some  obstacles,  it  being  diffi- 
cult to  saturate  in  a  short  time  thick  paper  with  sulphuric 
acid  and  to  remove  the  latter  rapidly.  In  this  case  two  or 
more  breadths  of  paper  are  treated,  each  by  itself,  with 
sulphuric  acid  and  the  first  wash  water,  and  then  passed 
together,  under  quite  heavy  pressure,  between  rolls.  The 
surfaces  of  the  breadths  of  paper  are  at  this  time  still  suffi- 
ciently sticky  to  make  it  possible  to  combine  the  breadths 
so  intimately  to  a  single  one,  that  the  joint  cannot  be  seen 
even  by  examining  the  cross  section  of  the  dried  parchment 
with  the  microscope.  By  the  use  of  an  apparatus  of  suit- 
able construction,  as  many  as  four  breadths  may  thus  be 
combined  in  one  and,  though  the  thickness  of  the  latter 
does  not  exceed  that  of  ordinary  drawing  paper,  its  strength 
is  actually  surprising.  Particular  care  must  be  taken  in 
washing  parchment  of  such  special  thickness,  as  it  would  in 
a  short  time  be  decomposed  if  a  small  quantity  of  sulphuric 
acid  should  happen  to  remain  in  its  interior. 

RENDERING   PARCHMENT    PAPER    FLEXIBLE. 

If  parchment  paper  is  to  be  deprived  of  its  characteristic 
stiffness  and  hardness  and  to  be  rendered  flexible,  the  object 
may  be  attained  by  suitable  treatment  with  strongly  hy- 


VEGETABLE    PARCHMENT.  89 

groscopic  bodies,  glycerin  being  especially  adapted  for  the 
purpose,  as  it  is  perfectly  harmless  and  there  can  be  no 
objection  to  the  use  of  a  material  treated  with  it,  for  wrap- 
ping up  articles  of  food.  Parchment  not  intended  for  the 
latter  purpose  may  be  rendered  flexible  by  the  use  of  a  con- 
centrated solution  of  magnesium  chloride,  calcium  chloride 
or  of  another  highly  hygroscopic  salt.  The  operation  is 
carried  on  as  follows :  The  finished  parchment,  before  it 
has  been  dried,  is  allowed  to  run  over  a  roll  dipping  par- 
tially into  a  vessel  containing  concentrated  glycerin,  a  thin 
layer  of  the  latter,  regulated  by  a  scraper,  adhering  to  the 
roll  and  being  transferred  to  the  parchment.  Parchment 
thus  treated  does  not  contract  very  much  in  drying  and 
remains  flexible  to  a  certain  degree. 

By  reason  of  its  great  density  parchment  paper  is  easily 
colored,  the  separation  of  the  coloring  matter  in  it  being 
readily  effected  by  placing  it  in  a  suitable  solution.  Ani- 
line colors  are  generally  employed,  fuchsin  being  used  for 
red.  The  alcoholic  solution  of  fuchsin  is  poured  into  boil- 
ing water  and  when  thoroughly  distributed  in  it,. the  parch- 
ment is  introduced.  For  blue,  water-soluble  blue  or  indigo 
carmine  is  used  ;  for  violet,  aniline-violet,  or  the  parchment 
is  first  colored  red  and  then  blue.  Yellow  is  obtained  with 
picric  acid  ;  orange,  with  fuchsin  and  picric  acid  ;  and  green, 
with  picric  acid  and  indigo-carmine. 

The  behavior  of  vegetable  parchment  towards  the  ordi- 
nary adhesive  agents,  such  as  mucilage,  paste,  glue,  etc.,  is 
very  unfavorable,  they  either  do  not  adhere  at  all  or  crack 
off  very  readily.  A  somewhat  better  adhesion  is  effected  by 
first  applying  alcohol,  and  then  the  adhesive  agent  to  the 
parts  of  the  parchment  to  be  joined  together,  or  by  laying 
a  strip  of  very  thin  ordinary  paper  between  them.  The 
best  material  for  the  purpose  of  joining  together  parchment 
paper  is  chromium  glue,  prepared  by  allowing  glue  to  swell 
up  in  water  to  which  a  quantity  of  potassium  dichromate 
equal  to  2  per  cent,  of  the  weight  of  the  dry  glue  has  been 


90  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

added.  When  swelled  up,  the  glue  is  dissolved  by  heating 
in  water,  the  solution  being  kept  in  the  dark  until  used. 
Chromium  glue  is  used  by  coating  the  pieces  to  be  joined 
with  the  solution,  pressing  them  together  and  exposing 
them  to  the  light,  the  chromium  glue  being  thereby  con- 
verted into  an  insoluble  combination  which  only  swells  up, 
without,  however,  dissolving  if  brought,  even  for  a  longer 
time,  in  contact  with  water. 

Vegetable  parchment  finds  many  applications.  It  is 
made  into  very  strong  pads  for  certain  important  writings, 
is  employed  for  the  manufacture  of  receptacles  for  articles  of 
food,  for  instance,  sausage  casings,  further  for  durable  book 
bindings,  etc.,  and  large  quantities  of  it  are  also  used  for 
osmotic  purposes,  it  possessing  the  property  of  allowing  the 
passage  of  fluids,  such  as  solutions  of  salt,  sugar,  etc. 

VULCANIZED    CELLULOSE  (VULCANIZED    FIBRE). 

Under  this  name  a  material  is  brought  into  the  market 
by  some  English  factories  which,  as  regards  its  properties, 
is  claimed  to  be  very  suitable  as  a  non-conductor  of  heat 
and  for  insulating  electric  lines.  According  to  Foster  it 
consists  essentially  of  a  product  which,  as  regards  its  mode 
of  manufacture,  closely  resembles  vegetable  parchment,  but 
it  has  the  advantage  that  it  can  be  made  in  pieces  of  any 
desired  thickness,  which  with  vegetable  parchment  can  only 
be  done  within  very  narrow  limits. 

According  to  the  description,  vulcanized  fibre  is  prepared 
by  treating  cellulose  in  a  loose  form,  or  in  the  form  of  paper, 
with  a  fluid  consisting  chiefly  of  sulphuric  acid,  to  which, 
however,  have  been  made  such  additions  as  will  neutralize 
the  progressive  action  of  the  acid  when  allowed  to  remain 
for  a  longer  time  in  contact  with  the  vegetable  fibre.  This 
is  claimed  to  be  attained  by  dissolving  metallic  zinc,  and 
next  dextrin,  in  the  sulphuric  acid.  According  to  the  patent 
specification,  the  process  is  as  follows :  For  every  32  parts 
of  ordinary  sulphuric  acid  1  part  zinc  is  used,  the  mixture 


VEGETABLE    PARCHMENT.  91 

being  allowed  to  stand  quietly  till  all  the  zinc  is  dissolved 
and  the  fluid  has  again  acquired  the  ordinary  temperature. 
In  the  fluid  thus  obtained,  which  represents  a  solution  of 
zinc  sulphate  in  an  excess  of  sulphuric  acid,  dextrin  is  dis- 
solved, the  proportion  used  being  1  part  of  dextrin  to  4  parts 
of  solution. 

While,  as  previously  mentioned,  the  adhesive  power  of 
paper  treated  with  sulphuric  acid  alone,  disappears  in  a 
short  time  so  that  haste  has  to  be  made  in  combining  two 
or  more  breadths  of  paper,  paper  treated  in  the  above-men- 
tioned solution  retains  its  adhesive  and  cementing  powers 
for  a  much  longer  time,  so  that  any  number  of  breadths  can 
be  leisurely  combined  to  one  plate,  or  loose  cellulose  may 
be  shaped.  The  finished  articles  are  first  treated  with  solu- 
tion of  common  salt  in  water,  and  finally  completely  freed 
from  adhering  salts  by  long-continued  washing  with  water. 
In  the  common-salt  bath  a  transformation  is  claimed  to 
take  place,  so  that  sodium  sulphate  and  zinc  chloride  are 
formed  which  can  be  readily  removed  by  washing. 

Very  thick  plates  or  other  thick  articles  may,  it  is 
claimed,  be  prepared  from  the  mass  by  coating  the  parts  to 
be  cemented  together  with  the  above-described  solution,  by 
which  they  are  rendered  adhesive  and  can  be  made  into  a 
single  piece  by  pressing  or  rolling. 

Vulcanized  fibre  is  found  in  commerce  in  two  forms, 
namely,  as  a  hard  mass  closely  resembling  wood  in  its 
properties,  and  as  a  soft,  flexible  and  elastic  substance  be- 
having similarly  to  leather.  The  hard  mass  can  be  worked 
with  the  knife  and  saw,  can  be  planed  and  turned,  and,  in 
a  fresh  state,  can  by  pressure  be  molded  into  any  desired 
shape ;  two  pieces  may  be  glued  together  like  wood.  On 
account  of  being  insensible  to  moisture  and  air,  and  by 
reason  of  its  exceedingly  slight  power  of  conducting  elec- 
tricity, the  mass  is  claimed  to  be  especially  suitable  for  the 
manufacture  of  insulators  for  electrical  purposes.  The 
elastic  mass  is  recommended  for  all  purposes  for  which,  at 


92  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

the  present  time,  leather  or  vulcanized  rubber  is  generally 
used,  for  instance,  for  packing,  valves,  etc. 

In  the  description  given  above  the  statements  made  in 
the  patent  specifications  have  been  accurately  followed,  and 
an  attempt  has  been  made  to  prepare  vulcanized  fibre  in 
accordance  with  them,  but  entirely  satisfactory  results  could 
not  be  obtained.  While  it  cannot  be  denied  that  parch- 
mentizing  in  the  fluid  containing  zinc  and  dextrin  takes 
place  more  slowly  than  when  working  with  sulphuric  acid 
alone,  it  was  impossible  to  obtain  a  mass  approaching  in 
solidity  that  of  wood,  or  even  of  horn.  The  incompact 
masses  could  be  quite  completely  freed  from  the  acid  and 
salts  by  repeated  treatment  with  water,  but  this  was  very 
incompletely  the  case  with  the  masses  subjected  to  stronger 
pressure,  so  that  in  drying  they  fell  to  pieces  by  reason  of 
sulphuric  acid  remaining  behind.  These  observations  jus- 
tify the  conclusion  that  several  things  essential  for  the  pre- 
paration of  the  vulcanized  fibre  mass  have  not  been  given 
in  the  patent  specification,  and  that  the  product  cannot  be 
made  by  simply  following  the  statements  contained  therein. 


V. 

PRODUCTION    OF   SUGAR    AND  ALCOHOL   FROM 
WOOD-CELLULOSE. 

THE  fact  that  cellulose  may  be  converted  into  ferment- 
able sugar  by  boiling  it  for  some  time  with  dilute  mineral 
acid  has  been  known  for  a  long  time.  Although,  theoreti- 
cally, the  conversion  of  cellulose  into  sugar  appears  a  very 
simple  process,  in  practice  on  a  large  scale  numerous  diffi- 
culties are  encountered.  Although  the  first  experiments  in 
this  direction  were  made  as  early  as  1854,  no  process  has 
been  discovered  up  to  the  present  time  which  could  be  used 
on  a  large  scale  with  any  prospect  of  success.  Nevertheless, 
it  would  not  seem  that  a  mistake  is  made  in  saying  that 
with  the  preparation  of  fermentable  sugar  from  cellulose  it 
will  be  exactly  the  same  as  with  the  production  of  pure 
cellulose  from  wood,  several  processes  for  that  purpose 
being- now  known  after  many  unsuccessful  experiments  had 
been  made,  and  that  a  method  for  the  production  of  fer- 
mentable sugar  from  wood-cellulose,  which  can  be  practi- 
cally applied,  will  also  be  finally  found. 

'In  all  the  attempts  to  obtain  fermentable  sugar  from  cel- 
lulose, wood  has  heretofore  been  employed  as  the  initial 
material,  and  that  the  results  obtained  with  its  use  have 
comparatively  given  but  little  satisfaction,  may  possibly  be 
chiefly  due  to  the  fact,  that  in  the  wood  the  individual  vas- 
cular bundles,  consisting  of  cellulose,  are  so  firmly  cemented 
together  by  the  lignin  as  to  make  them  in  a  high  degree 
proof  against  the  action  of  chemicals. 

Since  a  way  for  the  destruction  of  the  lignin  and  render- 
ing the  cellulose  accessible  to  the  action  of  chemicals  has 

(93) 


94  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

been  found  in  the  progress  made  in  this  direction  in  the 
manufacture  of  cellulose,  it  seems  reasonable  to  suppose 
that  the  time  is  drawing  nearer  when  the  question  as  re- 
gards the  production  of  larger  quantities  of  fermentable 
sugar  from  cellulose,  relatively  wood  substance,  will  also  be 
solved. 

OLDER    METHODS. 

The  first  attempts  to  produce  on  a  larger  scale  ferment- 
able sugar  from  wood  were  made  by  Zetterlund.  He  used 
fir  sawdust  and  boiled  it  with  8  per  cent,  of  its  weight  of 
hydrochloric  acid  under  a  pressure  of  1  \  pounds  per  square 
inch.  After  boiling  for  8  hours,  a  fluid  containing  3.38 
per  cent,  of  dextrose  was  obtained,  and  after  11  hours, 
4.38  per  cent.  Calculated  to  sawdust,  19.67  per  cent,  of 
the  latter  had  been  transformed.  The  fluid,  after  being 
separated  from  the  solid  residue,  was  neutralized  with  soda 
and  then  contained  a  quantity  of  common  salt  equal  to  the 
quantity  of  hydrochloric  acid  used.  The  fluid  was  brought 
into  fermentation  with  yeast  prepared  from  22  pounds  of 
malt  extract  and  the  fermented  mass  was  subjected  to  dis- 
tillation. The  yield  of  alcohol  from  990  pounds  of  saw- 
dust amounted  to  26.5  quarts. 

As  will  be  seen  from  the  figures  given  above,  there  is  a 
considerable  increase  in  the  quantity  of  sugar  obtained 
when  boiling  is  continued  for  more  than  8  hours.  As  the 
correct  basis  for  an  explanation  of  this  increase,  it  may 
well  be  assumed  that  at  the  beginning  of  the  action  of  the 
hydrochloric  acid  upon  the  wood,  the  tendency  of  the  entire 
chemical  process  was  to  attack  the  lignin  by  the  acid  and 
hence,  as  a  preparatory  operation,  a  gradual  laying  bare  of 
the  vascular  bundles  took  place.  Only  after  this  process 
had  progressed  to  a  certain  extent,  the  acid  commenced  to 
act  upon  the  cellulose  itself,  a  much  more  abundant  forma- 
tion of  sugar  taking  place  than  in  the  former  period. 

There  can  scarcely  be  any  doubt  that  with  the  use  of  a 
higher  pressure  and  longer  boiling,  far  larger  quantities  of 


SUGAR    AND    ALCOHOL    FROM    WOOD-CELLULOSE.  95 

sugar  can  be  obtained  from  the  wood  than  with  Zetterlund's 
process. 

Since,  for  the  purpose  of  obtaining  cellulose,  the  disinte- 
gration of  the  wood  may  also  be  effected  by  acid,  Bachet 
and  Machard  attempted  to  combine  the  production  of  sugar 
and  cellulose  in  one  process,  so  that  the  sugar  solution 
might,  in  a  certain  measure,  be  obtained  as  a  by-product  in 
the  manufacture  of  cellulose.  (See  p.  51). 

According  to  their  process,  the  wood  is  boiled  with  dilute 
acid,  the  acid  together  with  the  sugar  formed  washed  out 
with  water  and  the  remaining  mass  is  comminuted  in  a 
hollander,  bleached  with  chlorine  gas  and  finally  treated 
with  soda  lye.  The  product  thus  obtained  cannot  be  called 
either  mechanical  pulp  or  cellulose,  it  being  an  intermedi- 
ary between  both  products  but,  as  regards  its  properties, 
approaches  more  closely  bleached  mechanical  pulp  than 
cellulose.  On  a  large  scale  the  operation  is  carried  on  as 
follows:  The 'wood — fir  or  pine — is  cut  into  thin  discs. 
Four  thousand  four  hundred  pounds  of  these  discs  are 
brought  into  a  vat  together  with  2,000  gallons  of  water  and 
1,760  pounds  of  crude  hydrochloric  acid,  and  boiled  for  12 
hours  by  direct  steam,  hence  under  ordinary  pressure. 
The  resulting  fluid  having  been  separated  from  the  solid 
contents  of  the  vat,  is  neutralized  with  upwards  to  99  per 
cent,  of  calcium  carbonate  and  fermented  in  the  usual 
manner.  By  distilling  the  fermented  fluid,  a  corresponding 
quantity  of  alcohol  is  produced,  it  being,  however,  not  stated 
how  large  a  quantity  of  it  is  obtained  from  the  4,400 
pounds  of  wood  used. 

It  is  remarkable  that  according  to  Bachet  and  Machard's 
statements,  neutralization  of  the  acid  should  be  effected  by 
lime,  since  the  fluid  must  then  contain  a  corresponding 
quantity  of  calcium  chloride,  and  it  is  very  questionable 
whether  the  fermentation  of  the  sugar  can  proceed  regu- 
larly in  the.  presence  of  such  a  large  quantity  of  a  calcium 
salt. 


06  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

In  addition  to  the  processes  above  described,  there  are 
some  other  methods  for  the  production  of  alcohol  from 
wood,  of  which,  however,  but  little  is  known,  very  likely 
for  the  reason  that  satisfactory  results  were  not  obtained. 
One  of  these  methods  relates  to  the  production  of  alcohol 
from  beech.  In  this  case,  dilute  sulphuric  acid  is  made 
use  of  for  the  formation  of  sugar.  Boiling  is  effected  under 
a  comparatively  high  pressure — 7  to  8  atmospheres — and 
continued  for  10  to  12  hours.  The  final  result  was  a  com- 
paratively very  small  yield  of  raw  alcohol  of  a  disagreeable 
odor,  while  the  solid  mass  which  remained  in  the  boiler 
showed  a  dark-brown  color,  had  a  disagreeable  odor,  and 
was  not  fit  for  anything  but  fuel. 

The  failure  of  this  experiment  may  be  explained  from  the 
process  itself.  At  the  high  temperature  which  a  fluid 
standing  under  a  pressure  of  7  to  8  atmospheres  must 
acquire  before  it  reaches  the  boiling  point,  the  sugar  already 
formed  is  again  changed,  and  the  production  of  a  larger 
quantity  of  it  entirely  excluded.  The  poor  quality  of  the 
raw  alcohol  obtained  may  be  due  to  the  properties  of  the 
wood  used,  beech  containing  a  very  large  quantity  of  ex- 
tractive substances,  which  by  the  action  of  sulphuric  acid 
very  likely  yield  bodies  of  a  disagreeable  odor  characteristic 
of  the  raw  alcohol.  That  amongst  these  bodies  are  such  as 
gradually  acquire  a  dark  color  under  the  influence  of  the 
air,  is  shown  by  the  fact  that  the  raw  alcohol  in  a  very 
short  time  became  dark  brown.  By  repeated  rectification, 
this  disagreeable  odor  could  only  be  diminished,  its  entire 
removal  being  impossible,  and  neither  could  the  alcohol 
by  rectification  be  brought  to  a  state  in  which  it  remained 
colorless,  becoming  wine-yellow  when  for  a  short  time  ex- 
posed to  the  air. 

NATURE  OF  THE  WOOD  TO  BE  WORKED. 

The  nature  of  the  wood  to  be  worked  appears  to  exert 
great  influence  upon  the  yield  of  alcohol  in  general,  as  well 


SUGAR    AND    ALCOHOL    FROM    WOOD-CELLULOSE.  97 

as  upon  the  quality  of  the  product  itself.  Experiments 
made  in  this  direction  with  pure  cellulose  gave  much  more 
satisfactory  results  than  with  wood  itself,  and  the  alcohol 
obtained  could  be  quite  readily  purified  by  rectification. 
These  facts  serve  as  hints  of  how  to  proceed  in  order  to  ob- 
tain comparatively  large  yields  of  alcohol  of  sufficient 
purity,  as  well  as  that  great  care  has  to  be  exercised  in  the 
selection  of  the  wood  to  be  used. 

Compact,  heavy  wood,  containing  large  quantities  of  ex- 
tractive substances  may  at  the  outset  be  designated  as  un- 
suitable for  the  purpose.  Such  wood  contains  considerable 
quantities  of  lignin,  tannin,  coloring  matter  and  other  ex- 
tractive substances  which  cannot  be  converted  into  sugar, 
and  hence  beech,  oak,  chestnut,  etc.,  are  not  available. 

The  conifers — pine,  fir,  spruce,  etc., — contain  large  quan- 
tities of  rosin  and  volatile  oils,  the  presence  of  which  has  a 
disturbing  effect.  Hence  there  is  but  little  choice  as  re- 
gards the  selection  of  wood  for  the  production  of  alcohol, 
and  only  varieties  with  a  white,  incompact  and  soft  wood 
can  be  used  to  advantage.  Of  the  European  varieties  of 
wood,  aspen,  poplar,  willow  and  linden,  are  the  most  suit- 
able materials  for  the  purpose. 

A  few  remarks  may  here  be  made  in  reference  to  the  ap- 
paratus to  be  used  and  the  mode  of  procedure  in  general. 
Since  in  starting  a  plant  as,  for  instance,  one  required  for 
working  wood,  machinery  plays  an  important  part,  the  entire 
execution  of  the  plan  is  generally  left  to  an  engineer  who 
puts  up  apparatus,  boilers  for  boiling  under  pressure,  etc., 
according  to  his  own  judgment  without  consulting  the 
chemist  as  to  the  conditions  the  apparatus  is  to  meet.  The 
order  in  which  the  plant  is  to  be  managed  is  also,  as  a  rule, 
indicated  by  the  engineer  who,  in  most  cases,  does  not  pos- 
sess the  chemical  knowledge,  which  is  absolutely  required 
if  favorable  results  are  to  be  obtained. 

Thus  it  may  happen,  as  it  actually  did  in  the  above- 
mentioned  example,  that  wood  is  boiled  under  pressure 

7  '     :-•' 


98  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

with  a  comparatively  very  large  quantity  of  sulphuric  acid, 
the  temperature  becoming  thereby  so  high  that  the  newly- 
formed  sugar  was  largely  reconverted  into  other  combina- 
tions and  the  yield  in  consequence  was  so  small,  that  the 
entire  expensive  plant  had  to  be  abandoned  and  the  ma- 
chinery sold  for  old  metal. 

MORE    MODERN    METHODS. 

If  the  working  of  wood  for  the  production  of  alcohol  is  to 
be  carried  on  in  a  rational  manner,  i.  c.,  in  accordance  with 
the  laws  of  chemical  science,  it  is  absolutely  necessary  to 
proceed  according  to  the  following  principles : 

The  soft,  white  wood  cut  into  thin  discs  should  for  a  con- 
siderable time  be  submerged  in  running  water,  the  object  of 
this  soaking  being  to  free  the  wood  as  much  as  possible 
from  water-soluble  extractive  matter  such  as  albumen, 
tannin  and  other  substances,  so  that  only  the  vascular 
bundles  cemented  together  by  the  lignin  remain  behind. 

The  wood  when  sufficiently  soaked  is  to  be  cut  into  small 
pieces  as  if  it  were  to  be  worked  for  cellulose  by  the  soda  or 
sulphite  process.  This  reduction  is  necessary,  on  the  one 
hand,  to  give  the  wood  a  very  large  surface,  thus  present- 
ing to  the  acid  many  points  of  attack,  and  on  the  other, 
because  the  residue  which  remains  behind  after  treating 
the  wood  with  acid,  can  thus  be  best  utilized  for  the  prepar- 
ation of  cellulose. 

Hydrochloric  acid  is  most  suitable  for  converting  the 
cellulose  into  sugar,  it  being  preferable  to  sulphuric  acid, 
if  only  for  the  reason  that  even  at  a  high  temperature  it 
does  not  form  brown,  coal-like  combinations  from  the  cell- 
ulose. 

Since  by  boiling  under  increased  pressure  a  much  larger 
quantity  of  sugar  can  be  obtained  than  by  boiling  under 
ordinary  conditions,  an  increased  pressure  will  have  to  be 
worked  with,  and  the  use  of  a  closed  boiler  would,  therefore, 
seem  to  be  one  of  the  conditions  for  attaining  favorable  re- 
sults. 


SUGAR    AND    ALCOHOL    FROM    WOOD-CELLULOSE.  99 

For  boiling,  a  vertical,  iron  vessel  furnished  with  a  re- 
movable lid,  steam  heating  and  safety-valve  will  have  to 
be  used.  Since  iron  is  vigorously  attacked  by  the  vapors 
of  hydrochloric  acid,  the  boiler  will  have  to  be  lead-lined, 
this  metal  being  least  attacked  by  the  vapors.  In  order  to 
save  the  lead-lining,  a  wooden  vessel  which  almost  fills  the 
boiler,  may  be  placed  in  the  latter.  This  wooden  vessel 
serves  for  the  reception  of  the  comminuted  wood  and  the 
fluid,  and  when  boiling  is  finished  and  its  fluid  contents 
have  been  discharged,  it  is  lifted  from  the  boiler  by  means 
of  a  hoist. 

When  the  boiler  has  been  charged  with  the  comminuted 
wood  and  dilute  hydrochloric  acid,  the  apparatus  is  closed 
air-tight  and  the  fluid  is  brought  to  boiling  by  means  of 
steam  of  such  a  tension  that  the  contents  of  the  boiler  are 
not  heated  to  above  230°  or  233.6°  F.,  boiling  being  con- 
tinued for  a  suitable  time,  and  very  likely  10  to  12  hours 
will  be  required  until  a  sufficiently  large  quantity  of  sugar 
will  have  formed.  There  being  no  data  on  hand  regard- 
ing the  time  required  for  obtaining  the  largest  possible 
quantity  of  sugar,  and  this  time  varying  probably  for 
every  variety  of  wood  and  for  different  concentrations  of 
the  acid,  it  must  be  determined  by  experiments.  Such  ex- 
periments or  tests  are  made  by  taking  every  hour  samples 
from  the  boiler  and  determining  the  content  of  sugar.  If, 
in  the  disintegration  of  wood,  the  conditions  should  be 
similar  to  those  in  the  disintegration  of  starch  for  the  pur- 
pose of  producing  grape-sugar,  it  will  be  observed  by^  the 
samples  that  the  quantity  of  sugar  formed  within  a  certain 
time  increases  quite  regularly  until  a  period  is  reached 
when  the  further  formation  of  sugar  becomes  very  sluggish, 
so  that  for  reasons  of  expediency  the  operation  may  be  con- 
sidered finished. 

Since  the  hydrochloric  acid  does  not  undergo  a  change  in 
converting  a  portion  of  the  cellulose  into  sugar,  but  acts  by 
its  mere  presence,  the  fluid  at  the  end  of  the  operation  will 


1QO  CELLULOSE,  AND    CELLULOSE    PRODUCTS.    '     . 

contain  as  much  free  hydrochloric  acid  as  was  originally 
present,  and  this  acid  has  to  be  removed  as  far  as  possible. 
This  may  be  effected,  when  the  formation  of  sugar  is  com- 
plete, by  connecting  the  lid  of  the  boiler  with  a  lead  cool- 
ing coil  in  a  cooling  vat,  and  distilling  off  a  portion  of  the 
fluid,  boiling  being  continued  under  the  ordinary  pressure. 
The  greater  portion  of  the  hydrochloric  acid  present  in  the 
fluid  will  thereby  escape  together  with  the  steam,  and  will 
be  again  condensed  in  the  cooling  coil.  The  dilute  hydro- 
chloric acid  thus  obtained  may  be  used  for  the  next 
operation.  Distillation  may  be  continued  until  the  fluid 
contains  only  3  per  cent,  of  free  acid,  when  the  operation 
is  interrupted. 

When  this  point  has  been  reached,  the  fluid  is  dis- 
charged from  the  boiler,  the  boiling  vessel  hoisted  from  the 
latter,  and  replaced  by  another  which  has  in  the  meantime 
been  charged  with  wood,  so  that  with  the  exception  of  the 
short  time  required  for  emptying  and  recharging  the  boiler, 
the  operation  can  be  carried  on  without  interruption. 

The  unchanged  wood  remaining  in  the  boiler  is  still 
saturated  with  the  acid,  sacchariferous  fluid.  This  fluid 
is  obtained  by  repeatedly  washing  the  wood  with  water, 
but  it  cannot  be  recommended  to  combine  it  with  the 
fluid  first  obtained,  otherwise  the  sugar  solution  would  be 
too  much  diluted.  The  fluid  used  for  washing  the  wood 
is  utilized  in  the  next  operation  in  place  of  pure  water, 
the  hydrochloric  acid  as  well  as  the  sugar  contained  in  it 
being  thus  completely  exhausted. 

The  sugar  solution  discharged  from  the  boiler  is  now 
neutralized  with  soda  to  such  an  extent  that  its  content  of 
free  hydrochloric  acid  is  reduced  to  1  per  cent.,  the  compo- 
sition of  the  fluid  being  then  such  that  yeast  can  live  in  it, 
provided  it  is  furnished  with  the  requisite  quantity  of  nour- 
ishing salts. 

This  object  may  be  attained  by  adding  to  the  fluid  cooled 
to  about  86°  F«,  5  per  cent,  of  yeast  prepared  from  crushed 


SUGAR   AND    ALCOHOL    FROM    WOOD-CELLULOSE.          101 

malt.  It  is,  however,  also  possible  to  make  use  of  a  cheaper 
method  by  adding  directly  to  the  fluid  salts  serving  as  nu- 
triment of  the  yeast,  equal  parts  of  potassium  phosphate  and 
ammonium  phosphate  being  very  suitable  for  the  purpose. 
One  part  of  the  nourishing  salt  for  1000  parts  by  weight  of 
the  fluid  is  used.  These  salts  dissolving  with  ease  in  water, 
a  solution  of  them  is  prepared  in  a  small  quantity  of  the 
fluid  and  uniformly  distributed  throughout  the  sugar  solu- 
tion by  stirring. 

Fermentation  can  be  induced  either  by  freshly-compressed 
yeast  or  by  freshly-prepared  distillery  yeast.  With  the 
fluid  at  a  temperature  of  86°  F.,  propagation  of  the  yeast 
takes  place  very  rapidly,  and  in  a  short  time  the  fluid  is  in 
a  state  of  vigorous  fermentation.  Regarding  the  quantity 
of  compressed  yeast  to  be  used  it  may  be  said  that  J  part 
by  weight  of  it  suffices  for  100  parts  by  weight  of  the  sugar 
contained  in  the  fluid. 

The  fluid  is  now  left  to  itself  until  fermentation  is  fin- 
ished, which  with  the  high  temperature  at  which  it  was  in- 
duced, will  be  the  case  in,  at  the  utmost,  36  hours.  It  is 
then  drawn  off  from  the  yeast  at  the  bottom  of  the  vat,  and 
immediately  subjected  to  distillation.  The  yeast  need  not 
be  removed  from  the  vat  but  can  be  utilized  in  the  next 
operation. 

Distillation  of  the  fermented  fluid  should  be  effected  in 
an  apparatus  which  allows  of  the  alcohol  being  rectified  as 
far  as  possible,  i.  e.,  to  somewhat  above  96  per  cent.  Wood 
alcohol  always  has  a  peculiar  odor  due  to  small  quantities 
of  combinations,  the  chemical  nature  of  which  is  not  de- 
finitely known.  HOY; ever,  by  careful  rectification  these 
bodies  can  be  so  completely  separated  from  the  alcohol  that 
it  possesses  only  the  odor  of  the  pure  product. 

When  soft,  white  varieties  of  wood  are  in  the  above 
described  manner  treated  with  hydrochloric  acid,  the  resi- 
due remaining  behind  retains  its  color  unchanged,  provided 
the  acid  used  is  free  from  iron.  However,  ordinary  crude 


102  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

hydrochloric  acid,  which  will  have  to  be  used  when  working 
on  a  large  scale,  always  contains  a  certain  quantity  of  iron, 
and  the  wood  shows  generally  a  slightly  brownish  color,  so 
that  when  further  worked  to  cellulose  it  does  not  yield  an 
entirely  pure  white  product,  which  can,  however,  be  so 
made  by  bleaching. 

Supposing  that  20  per  cent,  of  the  weight  of  the  wood 
can  be  converted  into  fermentable  sugar,  and  assuming  that 
this  quantity  of  sugar  after  fermentation  and  deduction  of 
unavoidable  losses  yields  in  round  numbers  10  liters  of 
alcohol :  by  taking  the  value  of  1  liter  of  alcohol  at  only 
10  Pfennige  *  it  will  be  seen  that  the  alcohol  obtained  from 
100  kilogrammes  (220  Ibs.)  has  a  value  of  1  niark,f  and 
that  the  remaining  80  kilogrammes  (193.6  Ibs.)  of  wood  are 
available  for  further  working  into  cellulose.  Hence  the 
calculated  results,  even  with  such  small  yields  and  low 
price  of  the  alcohol  produced  as  have  been  assumed  above, 
are  by  no  means  unfavorable,  and  it  might  certainly  prove 
a  profitable  undertaking  for  a  chemist  to  investigate  closely 
the  subject,  working  especially  with  a  view  towards  increas- 
ing the  yield  of  sugar  from  the  wood. 

CLASSEN'S  PROCESS. 

The  chemist  Classen  has  recently  devoted  much  time  to 
the  solution  of  the  problem  of  producing  directly-ferment- 
able sugar  from  wood,  having  adopted  entirely  new  methods, 
which,  according  to  his  statements,  have  actually  resulted 
in  comparatively  large  yields. 

According  to  a  process  patented  by  him  the  wood  is  first 
treated  with  sulphuric  acid,  having  a  concentration  of  the 
so-called  chamber  acid — 50°  to  GO0  Be. — and  then  sub- 
mitted to  powerful  mechanical  pressure,  the  effect  of  the 
latter,  it  is  claimed,  being  to  convert  a  large  portion  of  the 

*  1  Pfennig  =  0.236  cent, 
f  1  Mark  — 23. 6  cents. 


SUGAR    AND    ALCOHOL    FROM    WOOD-CELLULOSE.          103 

cellulose  contained  in  the  wood  into  dextrose.  (?)  The  mass 
need  then  only  be  diluted  with  water  and  boiled  for  some 
time  at  the  ordinary  pressure  to  accomplish  complete  (?) 
conversion  into  dextrose. 

Air-dry  sawdust,  which  in  this  state  contains  in  round 
numbers  15  per  cent,  of  water,  is  used  as  raw  material.  A 
portion  of  the  sawdust  is  intimately  mixed  with  three- 
fourths  its  quantity  of  sulphuric  acid  of  57°  Be.,  a  mass  of 
a  peculiar  greenish  color  being  thereby  formed.  By  ex- 
tracting this  mass  with  water  a  fluid  is  obtained  in  which 
no  sugar  can  be  found.  By  subjecting  it,  however,  to 
strong  pressure  by  means  of  a  powerful  hydraulic  press  a 
vigorous  chemical  reaction  takes  place,  the  mass  becoming 
highly  heated  and  its  color  being  changed  to  nearly  black, 
so  that  it  presents  the  appearance  of  wood  which  has  been 
carbonized  by  highly  concentrated  sulphuric  acid.  On  ex- 
tracting the  pressed  mass  with  water  the  latter  shows  a  very 
distinctive  sugar-reaction. 

According  to  close  investigations,  it  is  claimed  that  in 
consequence  of  the  pressure,  the  greater  portion  (?)  of  the 
wood-fibre  is  converted  into  cellulose,  and  in  addition  there 
are  present  other  bodies  which,  as  regards  their  properties, 
occupy  intermediate  positions  between  dextrin  and  dextrose. 
For  the  conversion  of  all  (?)  the  dissolved  bodies  into  dex- 
trin, it  suffices  to  mix  the  pressed  mass  with  water  in  the 
proportion  of  1  part  of  the  substance  originally  used  to  4 
parts  of  water,  and  to  boil  it  for  half  an  hour  in  an  open 
vessel.  By  this  process  a  fluid  is  said  to  be  obtained  which 
is  free  from  the  intermediate  products  interfering  with  fer- 
mentation otherwise  found  in  dextrose  solutions  prepared 
from  wood. 

If  the  process  above  described  is  actually  available  in 
practice,  it  may  be  supposed  that  the  first  effect  produced 
by  the  sulphuric  acid  upon  the  wood  is  to  destroy  the  en- 
crusting substance — the  lignin — so  that  the  pure  cellulose 
becomes  accessible  to  the  further  action  of  the  acid.  It  re- 


104  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

mains  still  to  be  established  by  experiments,  whether  the 
conversion  of  this  cellulose  into  dextrose  cannot  be  attained 
by  simply  heating  the  green  mass  to  a  certain  temperature 
without  the  use  of  strong  pressure. 

A  decided  disadvantage  of  this  process  is,  however,  the 
use  of  a  quantity  of  sulphuric  acid  which  is  exceedingly 
large  in  comparison  with  the  quantity  of  wood  to  be 
worked,  amounting  in  round  numbers  to  75  per  cent,  of  the 
latter ;  and  to  bring  the  dextrose  solution  finally  obtained 
into  fermentation,  this  quantity  of  sulphuric  acid  must  be 
nearly  neutralized  by  the  addition  of  lime.  Hence,  it  will 
be  necessary  to  recover  the  considerable  quantity  of  dex- 
trose solution  adhering  to  the  resulting  gypsum  by  system- 
atic washing  of  the  latter.  The  quantities  of  gypsum 
which  would  finally  accumulate  in  carrying  on  the  opera- 
tion on  a  more  extensive  scale,  would  be  very  large  and 
difficult  to  utilize,  so  that  the  cost  of  producing  ferment- 
able sugar  according  to  this  process  would  be  comparatively 
quite  high. 

It  would  appear  that  the  inventor  of  the  above-described 
process  was  himself  not  entirely  satisfied  with  the  results, 
and  continued  his  investigations  in  regard  to  the  produc- 
tion of  dextrose  from  wood  in  another  direction.  A  note- 
worthy process,  also  patented  by  Classen,  is  based  upon  the 
principle  that  by  the  action  of  watery  sulphurous  acid  at  a 
higher  temperature,  wood-substance  is  disintegrated  to  such 
an  extent  that  the  presence  of  a  very  small  quantity  of 
sulphuric  acid  suffices  for  the  conversion  of  a  very  consid- 
erable quantity  of  cellulose  into  fermentable  sugar. 

In  the  commencement  of  the  operation  a  fluid  consisting 
of  a  concentrated  solution  of  sulphurous  acid  containing 
0.2  per  cent,  of  sulphuric  acid  is  used,  or  sulphurous  acid 
alone  is  employed,  the  latter,  at  a  certain  stage  of  the  pro- 
cess, being  partially  converted  into  sulphuric  acid  so  that 
at  the  moment  of  its  nascency  it  acts  upon  the  cellulose. 

The  maximum  yield  of  dextrose  is  obtained  by  conduct- 


SUGAR    AND    ALCOHOL    FROM    WOOD-CELLULOSE.          105 

ing  the  operation  so  that  the  formation  of  sulphuric  acid 
takes  place  at  a  period  when  the  temperature  in  the  boiler 
is  between  248°  and  293°  F.  In  this  case,  it  is  claimed, 
that  from  every  kilogramme  (2.2  Ibs.)  of  wood  (dry  sub- 
stance) at  least  300  grammes  (10.58  ozs.)  of  dextrose  are 
obtained,  of  which,  on  an  average,  80  per  cent,  is  ferment- 
able. Hence,  in  round  numbers  120  grammes  (4.23  ozs.) 
of  absolute  alcohol  would  be  obtained  from  1  kilogramme 
(2.2  Ibs.)  of  anhydrous  wood-substance. 

The  temperature  required  for  the  formation  of  dextrose 
after  the  wood  has  been  previously  disintegrated  by  the 
action  of  sulphurous  acid,  depends  on  the  nature  of  the  wood 
to  be  worked,  a  temperature  of  267°  F.  sufficing  for  birch, 
while  for  fir  one  of  upwards  to  293°  F.  is  necessary.  While 
a  certain  quantity  of  dextrose  is  without  doubt  formed 
below  these  temperatures,  it  is  a  comparatively  very  small 
one. 

The  production  of  sulphuric  acid  at  a  certain  stage  of  the 
process  may  be  effected  in  various  ways,  the  simplest 
niethod  being  to  introduce  into  the  vessel  atmospheric  air 
or  a  gas  mixture  rich  in  oxygen,  or  by  adding  manganese 
suboxide  or  peroxide,  which  yield  a  portion  of  their  oxygen, 
a  corresponding  quantity  of  sulphurous  acid  being  thereby 
converted  into  sulphuric  acid. 

From  what  has  been  said  above,  the  main  point  of  the 
process  consists  in  treating  the  wood  in  an  autoclave  with 
the  sulphurous  acid  solution  until  the  temperature  reaches 
248°  to  293°  F.,  then  bringing  about  the  formation  of  sul- 
phuric acid  and  continuing  heating  for  10  to  15  minutes 
longer. 

Although  Classen  appears  to  lay  great  stress  upon  the 
fact  that  the  sulphuric  acid  acts  at  the  moment  of  its  forma- 
tion upon  the  cellulose,  he  remarks  directly  in  connection 
with  the  description  of  his  process  given  above,  that  in  place 
of  sulphuric  acid,  a  mixture  of  sulphurous  acid  with  some 
other  inorganic  acid,  for  instance,  hydrochloric  acid  of  a 


106  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

concentration  of  0.2  per  cent,  or  more,  may  also  be  used. 
If  such  is  actually  the  case,  the  particular  action  which  the 
sulphuric  acid  is  claimed  to  exert  at  the  moment  of  its  forma- 
tion, is  virtually  eliminated,  and  the  use  of  sulphurous  acid 
for  the  disintegration  of  the  wood  remains  as  the  only  main 
feature  of  the  entire  process.  It  must  be  admitted  that  the 
figures  given  above  regarding  the  yield  of  fermentable 
sugar  are  excellent,  and  for  this  reason  alone  the  process 
deserves  serious  consideration. 

Experiments  made  by  Classen  to  effect  the  disintegration 
of  the  wood  by  means  of  chlorine  or  hypochlorides  yielded 
favorable  results  also.  The  wood,  together  with  a  half  per 
cent,  chlorine  water,  is  heated  to  between  248°  to  293°  F., 
and  sulphurous  acid  is  then  introduced  into  the  vessel  and 
rapidly  converted  into  sulphuric  acid  by  the  action  of  the 
chlorine. 

Another  process,  also  patented  by  Classen,  consists  in  the 
action  of  sulphuric  acid,  just  formed  from  sulphuric  anhy- 
dride, upon  the  wood.  Vapors  of  sulphuric  anhydride 
mixed  with  vapors  of  sulphur  dioxide  are  conducted  upon 
the  moist  sawdust.  The  sulphur  dioxide  on  coming  in 
contact  with  the  water  contained  in  the  sawdust  is  con- 
verted into  sulphurous  acid,  and  the  wood  is  by  the  latter 
disintegrated  in  the  manner  already  explained.  The  sul- 
phuric anhydride  on  coming  in  contact  with  the  water  is 
transformed  to  sulphuric  acid,  which  at  the  moment  of  its 
formation  is  said  to  possess  great  inverting  power.  Classen 
claims  to  effect  the  treatment  of  the  wood  with  sulphuric 
anhydride  in  revolving  lead-lined  drums,  and  accelerates 
the  operation  by  previously  heating  the  drums  to  from  86° 
to  104°  F.  The  resulting  mass  is  then  pressed  until  it  is 
hard  and  of  a  dark  color,  when  it  is  treated  with  four  times 
its  quantity  of  water,  and  after  neutralization  of  the  acid  is 
subjected  to  fermentation.  Classen  has  found  it  suitable  to 
heat  the  mass  treated  with  sulphuric  anhydride  for  some 
time  in  a  closed  vessel  to  between  257°  and  275°  F.,  the 
formation  of  sugar  being  thereby  still  further  increased. 


SUGAR    AND    ALCOHOL    FROM    WOOD-CELLULOSE.          107 

Sulphurous  acid  possessing  in  an  uncommon  degree  the 
property  of  checking  fermentation,  it  would  appear  abso- 
lutely necessary  to  free  the  fluid  containing  dextrose  com- 
pletely from  it  before  submitting  it  to  fermentation,  and 
this  can  only  be  with  certainty  effected  by  boiling  continued 
for  a  longer  time.  Only  when  a  test  of  the  fluid  as  to  the 
presence  of  sulphurous  acid  yields  a  negative  result,  the  free 
acid  still  present  can  be  almost  completely  neutralized,  and 
the  fluid  set  for  fermentation.  The  presence  of  a  smaller 
quantity  of  acid  does  not  impede  fermentation,  but  is  rather 
beneficial,  since  yeast  thrives  very  well  in  an  acid  fluid, 
while  certain  other  organisms,  which  bring  about  by- 
fermentations,  cannot  develop  it. 

A  further  modification  of  Classen's  process  consists  in  the 
wood  being  simultaneously  exposed  to  the  action  of  two 
acids  at  the  moment  of  their  liberation.  The  wood  is  first 
heated,  together  with  sulphurous  acid,  to  between  266°  and 
293°  F.,  then  allowed  to  cool  to  248°  or  260°  F.,  when 
chlorine  water  is  introduced  into  the  fluid.  In  this  case, 
sulphuric  acid,  as  well  as  hydrochloric  acid,  is  formed,  and 
the  presence  of  both  of  these  acids  is  said  to  have  a  favora- 
ble effect  upon  the  conversion  of  cellulose  into  dextrin. 
The  quantity  of  chlorine  to  be  used  must  bo  sufficiently 
large,  so  that  at  least  0.2  per  cent,  of  sulphuric  acid  is  formed. 

If,  as  previously  stated,  120  grammes  (4.23  ozs.)  of  pure 
alcohol  can  be  obtained  from  1  kilogramme  (2.2  Ibs.)  of 
perfectly  dry  wood-substance  by  one  of  Classen's  processes, 
it  would  be  well  adapted  for  working  on  a  large  scale. 
Regarding  the  residue  of  substance  not  converted  into  dex- 
trose, it  could  very  likely  not  be  utilized  for  any  other 
purpose  than  for  burning  under  the  boilers  of  the  plant. 


VI. 

PREPARATION    OF   OXALIC    ACID    FROM   WOOD 
CELLULOSE. 

WHEN  an  organic  substance  is  heated,  together  with 
caustic  alkalies,  to  a  certain  quite  high  temperature,  it  is 
completely  decomposed,  and  among  the  products  of  decom- 
position is  always  found  a  certain  quantity  of  oxalic  acid. 
The  organic  substances  behave  thereby,  however,  in  such  a 
manner  that  from  bodies  of  animal  origin  but  small  quan- 
tities of  oxalic  acid  can  be  obtained,  while  substances 
derived  from  the  vegetable  kingdom  yield  such  a  large 
quantity  of  it  that  it  may  almost  be  designated  as  the 
chief  product  of  the  processes  of  decomposition.  A  series 
of  exact  experiments  with  various  substances  of  vegetable 
origin  have  led  to  the  result,  that  the  yield  of  oxalic  acid  is 
the  greater  the  more  closely  the  vegetable  substances  used 
approach  the  pure  carbohydrates  in  their  composition. 

In  accordance  with  this,  starch,  pure  cellulose,  etc.,  give- 
comparatively  the  largest  yields  of  oxalic  acid.  Since,  in 
addition  to  cellulose  and  lignin,  wood  contains  but  small 
quantities  of  other  bodies,  it  is  especially  suitable  for  the 
preparation  of  oxalic  acid,  and  the  more  so  as  sawdust, 
which  otherwise  is  of  but  little  value,  is  the  best  material 
for  the  purpose.  Though  there  is  considerable  difference 
in  the  various  kinds  of  wood  as  regards  the  extractive  sub- 
stances contained  in  them,  oak  being,  for  instance,  very 
rich,  and  poplar  very  poor  in  them,  this  fact  exerts  but 
little  influence  upon  the  yield  of  oxalic  acid,  which  justifies 
the  conclusion  that  the  extractive  substances — tannin,  col- 
oring matter,  etc. — as  well  as  the  wood-substance  itself,  may 

(108) 


OXALIC    ACID    FROM    WOOD-CELLULOSE.  109 

be  converted  into  oxalic  acid.  Since  all  substances  con- 
taining cellulose  form  an  equally  good  material  for  the 
production  of  oxalic  acid,  all  waste  products  of  this  kind 
may  be  used,  and  in  addition  to  sawdust,  waste  from  the 
manufacture  of  wood-cellulose  and  vegetable  parchment,  as 
well  as  scraps  of  tissue  of  vegetable  origin  may  be  utilized. 
The  formation  of  oxalic  acid  from  the  above-mentioned 
substances  takes  place  by  heating  them  together  with  a 
certain  quantity  of  caustic  alkali — potassium  or  sodium 
hydroxide,  or  a  mixture  of  both — to  above  392°  F.  It 
may,  however,  be  mentioned  as  a  remarkable  fact  that 
sodium  hydroxide,  when  used  by  itself,  gives  but  a  very 
small  yield  of  oxalic  acid,  while  caustic  potash  forms  con- 
siderably larger  quantities,  and  the  best  results  are  obtained 
when  both  the  alkalies,  mixed  in  a  certain  proportion,  are 
allowed  to  act  upon  the  saw-dust.  There  is  no  theoretical 
explanation  of  these  facts,  which  have  been  established  by 
experiments  made  with  the  greatest  exactness. 


According  to  investigations  made  in  this  direction  by 
Thorn,  50  parts  of  sawdust  heated  with  100  parts  of  caustic 
soda  to  a  temperature  of  392°  F.  yield  a  quantity  of  crys- 
tallized oxalic  acid  equal  to  30  per  cent.  By  doubling  the 
quantity  of  caustic  soda  a  greater  yield  is  obtained.  Thus 
25  parts  of  sawdust  heated  with  100  parts  of  caustic  soda 
yielded,  when  melted  in  a  dish  at  a  temperature  of  464°  F., 
a  quantity  of  oxalic  acid  which,  calculated  to  100  parts  of 
sawdust,  amounted  to  42.30  per  cent.  However,  an  ex- 
periment made  with  the  same  quantities  of  both  substances 
spread  out  in  a  thin  layer  and  heated  to  464°  F.  resulted  in 
a  yield  of  52.14  per  cent. 

Further  investigations  by  Thorn  refer  to  the  quantities 
of  oxalic  acid  which  can  be  obtained  by  the  action  of  a 
mixture  of  caustic  soda  and  caustic  potash  upon  sawdust. 
Thorn  extended  these  investigations  still  further  by  examin- 


110  'CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

ing  into  the  behavior  of  the  various  mixtures  when  they 
were  melted  together  with  sawdust  in  dishes,  or  when  the 
masses  were  heated  in  thin  la}'ers.  The  figures  indicating 
the  yield  of  oxalic  acid  under  these  different  conditions  give 
at  the  same  time  a  hint  of  how  the  manufacture  has  to  be 
carried  on  in  order  to  obtain  the  greatest  possible  yield. 

1.  Yields  of  oxalic  acid  by  heating  sawdust  with  a  mix- 
ture of  caustic  soda  and  caustic  potash  in  thin  layers — 2 
parts  of  alkali  hydroxide  to  1  part  of  sawdust  were  used. 

Proportion  between  caustic       Temperature,        Yield  of  oxalic  acid  from 

potash  and  caustic  soda.  °  F.                    100  parts  of  wood. 

20  80  374  19.78 

20  80  392  21.50 

20  80  464  30.04 

30  70  374  21.38 

30  70  464  38.39 

40  60  374  1-1.00 

40  (50  £92  30.35 

40  GO  464  to  473  43.70 

50  50  392  25.76 

50  50  464  to  473  39.04 

60  50  392  £0.57 

CO  40  464  to  473  42.67 

80  20  392  to  428  45.59 

80  20  464  61.32 

90  10  464  64.24 

100  464  to  473  65.57 

By  treating  the  sawdust  with  one  of  the  mixtures  of 
caustic  alkalies  given  above,  its  color  is  changed  as  soon  as 
the  temperature  exceeds  284°  to  302°  F.,  becoming  at 
first  brownish,  which  soon  yields  to  a  greenish-yellow  tone. 
The  mass  then  acquires  a,  pasty  condition,  and  at  356°  F. 
evolves  heavy  nebulous  vapors.  That  at  this  temperature 
reaction  commences  to  be  most  energetic  is  evident  from 
the  fact  that  the  action  continues  even  if  further  heating 
is  entirely  interrupted.  The  temperature  of  the  mass  then 
gradually  rises  to  above  GSO°  F.,  the  mass  swells  up, 
evolves  a  large  quantity  of  combustible  gases  and  finally 


OXALIC    ACID    FROM    WOOD-CELLULOSE.  Ill 

carbonizes  completely  when  a  mixture  of  90  parts  of  caustic 
soda,  10  parts  of  caustic  potash  and  50  parts  of  wood  has 
originally  been  used.  This  proves  that  with  the  use  of  a 
mixture  containing  such  a  small  quantity  of  caustic  potash 
the  production  of  somewhat  larger  quantities  of  oxalic  acid 
would  be  impossible  as  the  temperature  of  the  mass  could 
not  be  regulated. 

In  the  same  degree  as  the  quantity  of  caustic  potash  in 
the  mixture  is  increased  and  that  of  caustic  soda  is  de- 
creased, the  reaction  takes  place  less  violently,  and  it  is 
possible  to  maintain  the  temperature  of  the  mass  within  the 
limit  of  464°  F. 

According  to  the  series  of  figures  given  above  the  best 
proportion  between  caustic  potash  and  caustic  soda  would 
be  to  use  80  parts  of  caustic  potash  to  20  parts  of  caustic 
soda,  or  90  parts  of  the  former  to  10  of  the  latter.  The 
temperature  has  to  be  raised  to  above  464°  F.  in  order  to 
obtain  a  yield  of  over  GO  per  cent,  of  oxalic  acid. 

As  will  be  seen  from  the  above-mentioned  figures,  a  con- 
siderably larger  yield  of  oxalic  acid  is  obtained,  if  the  mix- 
ture be  heated  in  a  thin  layer,  the  great  advantage  of  this 
mode  of  procedure,  when  working  on  a  large  scale,  consist- 
ing in  the  fact  that  the  temperature  of  a  mass  can  be  more 
readily  kept  within  the  prescribed  limits  than  when  work- 
ing in  deep  vessels.  For  this  purpose,  Thorn  has  deter- 
mined the  following  proportions : 

Proportion  between  caustic  Temperature.       Yield  of  oxalic  acid  from 

potash  and  caustic  soda.                  °  F.  100  parts  of  wood. 

0            100  392  to  408  33.14 

10             90                          446  58.36 

20      80  464  to  494  74.76 

30      70  464  to  494  76.77 

40      CO  464  to  494  80.57 

00      40  464  to  494  80.08 

80      20           473  81.24 

100               0  464  to  494  81.23 

Solutions  of  quite  high  concentration  (40°   Be*.)  of  the 


112  CELLULOSE,  AND    CELLULOSE    TEC-DUCTS. 

caustic  alkalies  containing  potash  and  soda  in  appropriate 
proportions  are  first  prepared,  and  heated  to  the  boiling 
point.  The  sawdust  is  then  introduced,  the  proportions 
being  so  chosen  that  for  2  parts  of  alkali  hydroxide  one 
part  of  wood  is  used.  In  introducing  the  sawdust  care 
should  be  taken  to  see  that  it  is  uniformly  distributed 
throughout  the  fluid  and,  if  the  latter  had  a  concentration 
of  40°  Be.,  it  will  be  completely  absorbed  by  the  sawdust. 

The  mixture  is  then  evenly  spread  out  upon  iron  pans 
in  layers  not  exceeding  0.39  inch  in  thickness  and  heated 
as  uniformly  as  possible,  the  premature  melting  of  the  mass 
being  as  far  as  possible  prevented  by  frequent  stirring. 
However,  as  the  temperature  soon  rises  above  392°  F.,  par- 
tial fusion  can  no  longer  be  prevented,  and  the  mass  becomes 
moist  and  crummy.  Heating  is  continued  for  1  to  1 J  hours, 
the  temperature  being  only  gradually  allowed  to  rise  to 
494°  F. 

As  shown  by  the  table  given  above,  a  mixture  of  40 
parts  of  caustic  potash  and  60  parts  of  caustic  soda  gives 
exactly  the  same  yield  of  oxalic  acid  as  pure  caustic  potash 
by  itself,  but  the  price  of  the  latter  being  much  higher  than 
that  of  caustic  soda,  it  will  be  of  advantage  to  use  in  prac- 
tice the  two  alkalies  in  the  proportion  given  above. 
••-.The  turbulent  reaction  during  fusion  may,  it  is  claimed, 
be  prevented,  so  that  the  preparation  of  oxalic  acid  takes 
place  quietly  and  smoothly,  by  adding  to  the  mixture  of 
sawdust  and  alkalies  heavy  hydrocarbons,  for  instance, 
machine  oil  or  vaseline  oil,  and,  according  to  Capitaincs 
and  Hertlings,  who  have  patented  a  process  for  this  pur- 
pose, the  use  of  caustic  soda  by  itself  suffices  for  the  forma- 
tion of  abundant  quantities  of  oxalic  acid.  They  use  a 
soda  lye  of  1.35  specific  gravity  in  the  proportions  of  40 
parts  of  sodium  hydroxide  to  20  parts  of  sawdust  and  1.5 
parts  of  hydrocarbon  combinations.  The  temperature  need 
not  exceed  392°  F.,  and  the  resulting  yield  of  oxalic  acid  is 
claimed  to  amount  to  140  parts  for  every  100  parts  ofyvcod. 


OXALIC    ACID    PROM    WOOD-CELLULOSE.  113 

PREPARATION    OF    OXALIC    ACID    ON    A    LARGE    SCALE. 

With  the  use  of  the  process  introduced  by  Thorn,  the 
preparation  of  oxalic  acid  is  divided  into  the  following 
operations  : 

Preparation  of  the  mixed  caustic  lyes  and  their  concen- 
tration by  evaporation  to  a  specific  gravity  of  1.35. 

Mixing  the  lye  with  the  sawdust  and  heating  the  mix- 
ture to  the  maximum  temperature  to  be  used. 

Production  of  sodium  oxalate  from  the  melt,  conversion 
of  it  into  calcium  oxalate,  and  separation  of  the  oxalic  acid 
from  the  latter ;  recrystallization  of  the  crude  oxalic  acid. 

In  preparing  the  mixed  lyes  the  content  of  pure  potas- 
sium carbonate  and  sodium  carbonate  in  the  potash  and 
soda  to  be  used  has  first  to  be  determined,  and  the  two  salts 
must  be  mixed  in  such  a  proportion  that  the  lye  contains 
exactly  40  parts  of  caustic  potash  and  caustic  soda.  The 
solution  of  the  salts  is  made  caustic  in  the  usual  man- 
ner by  means  of  quicklime,  and  evaporated  in  iron  pans 
to  1.35  specific  gravity.  It  is  then  immediately  mixed  with 
the  sawdust  in  the  proportion  of  1  part  of  the  latter  to  2 
parts  of 'alkali. 

MELTING    APPARATUS. 

The  apparatus  for  heating  the  mass  to  the  maximum 
temperature  required  for  the  formation  of  oxalic  acid  must 
be  of  such  a  nature  that  the  temperature  of  the  mass  can  be 
readily  regulated,  and  that  the  workmen  are  completely 
protected  from  the  vapors  evolved  from  the  mass  during 
heating.  These  vapors  have  a  troublesome  effect  upon  the 
respirator}7  organs  and  eyes,  and  provision  for  their  imme- 
diate removal  has  therefore  to  be  made.  This  may  be 
effected  by  placing  over  the  plates  upon  which  heating 
takes  place,  a  jacket  extending  down  as  far  as  possible  with- 
out impeding  the  work.  The  jacket  terminates  above  in  a 
shaft  in  which  a  very  strong  current  of  air  is  produced  by  a 
steam  ejector  or  a  fan.  In  this  manner  the  vapors  arising 
8 


114  CELLULOSK,  AND    CELLULOSE    PRODUCTS. 

from  the  plates  are  immediately  carried  away  and  blown 
into  a  high  chimney  or,  still  better,  under  the  grate  of  a 
fireplace. 

Since  in  heating  the  mass  the  temperature  must  not  ex- 
ceed 494°  F.,  it  would  seem  advisable  to  effect  heating  the 
plates  by  means  of  a  current  of  hot  air  or  superheated  steam, 
the  use  of  an  iron  box  4  to  6  inches  deep  and  6J  feet  long 
and  wide  being  most  suitable  for  the  purpose.  On  the  front 
of  the  box,  i.  e.t  the  side  turned  towards  the  workmen,  is  a 
pipe  through  which  the  heated  air  or  superheated  steam 
passes  into  the  box,  the  pipe  being  furnished  with  a  stop- 
cock, by  means  of  which  heating  can  be  regulated  as  desired. 

To  prevent  the  mass  spread  out  upon  the  surface  of  the 
box  from  acquiring  in  some  places  too  high  a  temperature, 
it  has  to  be  frequently  turned,  and  it  is  advisable  not  to  use 
for  this  purpose  iron  hand-rakes,  but  to  employ  a  mechan- 
ical contrivance  similar  to  that  used  in  malt-houses  for 
turning  the  malt  in  the  kiln.  Such  a  contrivance  can  be 
run  by  a  small  motor  so  that  the  entire  attention  of  the 
workmen  is  directed  towards  the  mass  in  hand. 

The  mass  having  been  spread  out  upon  the  iron  plate  in 
a  somewhat  thicker  layer  than  is  possible  without  the  use 
of  a  mechanical  turning  contrivance,  a  full  current  of  steam 
or  hot  air  is  immediately  admitted  for  the  purpose  of 
rapidly  heating  it  and  evaporating  the  water  still  adhering 
to  it.  To  prevent  caking,  the  turning  apparatus  is  at  once 
set  to  work. 

The  temperature  may  now  in  a  short  time  be  brought  to 
392°  or  410°  F.,  and  then  gradually  raised  to  464°  or  473° 
F.  At  this  temperature  the  mass  is  kept  for  from  one  to  one 
and  a  half  hours,  the  admission  of  steam  or  hot  air  being  so 
regulated  that  the  temperature  cannot  rise  any  higher. 
The  mass  is  now  considered  finished  and  removed  from  the 
heating  apparatus  by  means  of  iron  rakes. 


OXALIC    ACID    FROM    WOOD-CELLULOSE.  115 

WORKING  UP  THE  MELT. 

The  mass  contains  all  the  sodium  held  by  it  fixed  to 
oxalic  acid  ;  in  addition  it  contains  potassium  carbonate 
and  humus  substances  which  give  it  a  quite  dark  colora- 
tion. The  mass  is  immediately  thrown  into  a  vessel  con- 
taining a  certain  quantity  of  water,  which  is  in  a  short  time 
brought  to  boiling,  and  in  this  state  rapidly  dissolves  the 
sodium  oxalate.  It  is  advisable  to  place  in  the  vessel  a 
steam  coil  to  be  able  to  directly  heat  the  fluid.  Only 
enough  water  is  used  for  the  boiling  fluid  to  show  a  density 
of  35°  Be.  The  boiling  fluid  is  allowed  to  run  through  a 
filter  of  close  linen  into  a  vessel  in  which,  under  constant 
stirring,  it  is  rapidly  cooled  to  the  ordinary  temperature. 

Sodium  oxalate  dissolves  with  ease  only  in  boiling  water, 
it  being  but  slightly  soluble  in  cold  water  and,  hence,  by 
rapid  cooling,  a  pasty  mass  consisting  of  very  small  crystals 
of  quite  pure  sodium  oxalate  is  obtained.  This  pasty  mass 
is  treated  in  a  centrifugal  for  the  removal  of  the  mother-tye 
adhering  to  the  crystals. 

In  addition  to  a  very  small  quantity  of  sodium  oxalate, 
the  mother-lye  contains  the  total  quantity  of  the  potash 
used  in  the  form  of  potassium  carbonate,  and  the  humus 
substances  which  have  been  formed  by  heating  the  mass. 
The  mother-lye  is  utilized  by  converting  the  potassium  car- 
bonate into  caustic  potash  by  means  of  quick-lime,  and 
using  it  for  the  next  operation. 

However,  in  the  course  of  several  operations,  the  humus 
substances  accumulate  to  such  an  extent  in  the  mother-lye 
as  to  render  it  inadvisable  to  make  it  again  caustic.  It  is 
then  utilized  for  obtaining  pure  potassium  carbonate,  this 
being  effected  by  mixing  it  with  a  sufficient  quantity  of 
sawdust  to  make  a  mass  which  can  be  taken  up  with 
shovels.  This  mass  is  burnt  in  a  small  reverberatory  fur- 
nace, and  the  residue  of  ash  calcined  until  white.  It  then 
consists  of  almost  pure  potash  which  may  be  used  for  further 
operations. 


116  CELLULOSE,   AND    CELLULOSE    PRODUCTS. 

For  the  purpose  of  obtaining  pure  oxalic  acid  from  the 
crude  sodium  oxalate,  the  oxalic  acid  is  first  fixed  to  lime, 
and  the  resulting  calcium  oxalate,  which  dissolves  with  dif- 
ficulty, is  decomposed  by  sulphuric  acid,  a  solution  of  the 
oxalic  acid  being  thereby  obtained. 

This  operation  is  carried  on  by  dissolving  the  crude 
sodium  oxalate  in  boiling  water  in  a  vat  furnished  with  a 
stirrer  which  is  kept  in  constant  motion.  Milk  of  lime  is 
then  added  to  the  boiling  solution,  whereby  calcium  oxalate, 
which  dissolves  with  difficulty,  and  free  caustic  soda  are 
formed.  During  the  precipitation  of  the  calcium  oxalate, 
the  fluid  has  to  be  constantly  kept  near  the  boiling  point,  as 
only  under  this  condition,  the  precipitate  turns  out  granular 
and  settles  rapidly  on  the  bottom. 

A  sample  is  from  time  to  time  taken  from  the  vat,  fil- 
tered, acidified  first  with  an  excess  of  acetic  acid,  and  then 
solution  of  calcium  chloride  is  added.  If  the  sample  still 
gives  a  precipitate  it  is  an  indication  that  the  total  quantity 
of  the  sodium  oxalate  has  not  been  decomposed  and  more 
milk  of  lime  has  to  be  carefully  added.  When  the  sample 
shows  that  decomposition  is  complete,  the  stirrer  is  stopped, 
the  precipitate  allowed  to  settle,  and  the  supernatant  caustic 
lye  is  drawn  off.  The  precipitate  is  then  several  times 
washed  with  water,  and  the  wash-waters  are  combined  with 
caustic  lye  first  drawn  off.  The  total  quantity  of  fluid  thus 
obtained  is  evaporated  in  iron  pans  until  the  soda  lye  shows 
a  specific  gravity  of  1.35,  and  can  then  be  utilized  for  work- 
ing fresh  quantities  of  sawdust. 

The  calcium  oxalate  having  been  sufficiently  washed  is 
brought  into  a  lead-lined  vessel  upon  the  bottom  of  which 
rests  a  steam  coil,  and  mixed  with  a  sufficient  quantity  of 
water  to  form  a  thin  paste.  While  steam  is  being  intro- 
duced through  the  narrow  apertures  with  which  the  steam 
coil  is  furnished,  dilute  sulphuric  acid  (of  15°  to  20°  Be)  is 
allowed  to  run  in.  The  quantity  of  sulphuric  acid  required 
can  be  approximately  calculated,  but  in  order  to  separate 


OXALIC    ACID    FROM   WOOD-CELLULOSE.  117 

all  the  oxalic  acid  and,  at  the  same  time,  have  no  excess  of 
sulphuric  acid  in  the  fluid,  a  sample  of  the  latter  has  from 
time  to  time  be  tested.  This  is  effected  by  bringing  a  small 
quantity  of  the  white  precipitate  separated,  which  is  to  con- 
sist of  gypsum,  upon  a  filter,  washing  quickly  with  water, 
and  then  treating  the  mass  with  a  small  quantity  of  sul- 
phuric acid.  The  filtrate  now  obtained  is  mixed  with  solu- 
tion of  potassium  permanganate.  If  undecomposed  calcium 
oxalate  is  still  present  in  the  vat,  the  fluid,  which  imme- 
diately after  the  addition  of  the  potassium  permanganate 
appears  red,  becomes  discolored  by  the  decomposition  of  the 
latter.  If  the  fluid  remains  red,  decomposition  of  the  cal- 
cium oxalate  is  complete. 

PRODUCTION    OF    PURE    OXALIC    ACID. 

The  vat  now  contains  a  solution  of  oxalic  acid  in  water 
standing  over  the  precipitate  consisting  of  calcium  sulphate. 
The  solution  is  drawn  off,  the  precipitate  is  several  times 
washed  with  water  to  obtain  the  last  traces  of  oxalic  acid, 
and  the  oxalic  acid  solution  is  finally  highly  concentrated 
by  evaporation,  the  latter  being  effected  in  pans  very 
similar  to  those  used  for  evaporating  solutions  in  the  manu- 
facture of  tartaric  acid.  The  pans  consist  of  large,  shallow, 
lead-lined  wooden  boxes,  furnished  with  a  lead  heating 
coil.  Two  such  evaporating  pans  are  placed  one  above  the 
other  so  that  the  contents  of  the  one  placed  at  a  higher 
level  can  be  discharged  into  the  losver  pan. 

The  oxalic  acid  solution  is  first  brought  into  the  upper 
pan  and  evaporated  to  a  density  of  15°  Be.  It  is  then 
allowed  to  cool  and  run  into  the  lower  pan.  The  reason 
for  this  interruption  of  the  evaporation  is  that  the  dilute 
solution  of  oxalic  acid  contains  quite  a  large  quantity  of 
gypsum  in  solution,  and  the  latter  separates  completely 
only  when  the  fluid  has  acquired  the  above-mentioned  con- 
centration. After  removing  the  precipitated  g}'psum  from 
the  bottom  of  the  pan,  the  latter  is  again  charged  with 


118  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

crude  oxalic  acid  solution.  The  solution  in  the  lower  pan 
is  evaporated  to  30°  Be.,  and  then  left  to  crystallize  either 
in  large  stoneware  dishes  or  in  lead-lined  vats.  It  is  ad- 
visable repeatedly  to  stir  the  fluid  during  cooling,  small 
crystals  which  include  but  little  mother-lye  being  thereby 
obtained. 

When  the  fluid  in  the  crystallizing  vessels  has  become 
entirely  cold,  the  crystals  are  freed  as  far  as  possible  from 
mother-lye  by  treatment  in  a  lead-lined  centrifugal,  the 
crystals  of  crude  oxalic  acid  thus  obtained  being  available 
for  many  technical  purposes  as  their  slightly  brownish 
color  Is  not  objectionable. 

An  almost  chemically  pure  product  is  produced  from  the 
crude  oxalic  acid  by  dissolving  the  latter  in  the  smallest 
possible  quantity  of  boiling  water,  and  stirring  into  the  hot 
solution  a  small  quantity  of  finely-powdered  animal  char- 
coal. The  fluid  is  then  allowed  to  stand  until  the  animal 
charcoal  powder  has  settled  on  the  bottom  of  the  vessel, 
and  the  at  first  brownish  fluid  has  become  as  clear 
as  water.  The  hot  solution  is  then  allowed  to  run  in  a  thin 
stream  into  the  crystallizing  vessel  and  the  resulting  crys- 
tals are  completely  dried  by  whirling  in  a  centrifugal. 
The  oxalic  acid  thus  purified  contains  neither  free  sulphuric 
acid  nor  calcium  oxalate,  and  may  be  considered  a  highly 
refined  article. 

The  mother-lye  obtained  by  the  first  treatment  of  the 
crystals  of  crude  oxalic  acid  in  the  centrifugal  contains 
considerable  quantities  of  free  sulphuric  acid,  and  the  latter 
is  made  use  of  by  employing  the  mother-lye  in  the  next 
operation  of  decomposing  the  calcium  oxalate,  a  smaller 
quantity  of  sulphuric  acid  being  of  course  then  required. 


VII. 

VISCOSE  AND  VISCOID. 

THE  products  to  which  these  terms  have  been  applied, 
were  first  prepared,  in  1892,  by  Bevan,  Beadle  and  Cross. 
With  reference  to  their  properties  it  may  be  expected  that 
in  the  course  of  time,  they  will  find  extended  application  in 
the  industries,  because  from  them  can  be  prepared  cellulose 
in  a  perfectly  pure  state  in  the  form  of  completely  homo- 
geneous masses  of  any  desired  size,  and  it  is  possible  to 
color  them,  or  mix  them  with  a  solid  body  so  that  a  plastic 
mass  is  obtained,  the  nature  of  which  allows  of  the  most 
diverse  technical  applications. 

The  main  point  of  the  invention  lies  in  the  fact  that  a 
combination  of  cellulose  and  soda  forms,  on  addition  of 
carbon  disulphide,  a  substance,  the  solution  of  which  is 
called  viscose  on  account  of  its  uncommon  viscosity.  When 
such  a  soda-cellulose-carbon  disulphide  solution  is  exposed 
to  the  air,  a  gradual  disintegration  of  the  combination 
takes  place,  the  carbon  disulphide  evaporating  and,  in  many 
cases,  sulphuretted  hydrogen  also  escaping  from  the  mass. 
The  latter  becomes  constantly  of  greater  consistence,  and 
when  all  the  carbon  disulphide  has  finally  evaporated,  pure 
cellulose  intermingled  with  soda,  which,  however,  can  be 
readily  removed  by  washing,  remains  behind.  To  the 
cellulose  thus  obtained  the  term  viscoid  is  applied.  By  ex- 
posure to  a  higher  temperature  the  viscose  solution  is  in  a 
very  short  time  decomposed. 

The  progress  of  the  conversion  of  viscose  into  viscoid  can 
be  regulated  at  will  by  the  use  of  a  suitable  temperature, 
and  during  this  time  coloring-matter  or  any  desired  pulver- 

(119) 


120  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

ulent  bodies  may  be  incorporated  with  the  mass,  which 
becomes  constantly  more  thickly  fluid,  so  that  at  the  end  of 
the  operation  a  body  is  obtained  resembling,  as  regards  its 
properties,  wood,  horn  or  stone. 

If  no  additions  are  made,  there  is  finally  obtained  pure 
cellulose  in  the  form  of  a  white  mass,  which  in  thin  layers 
is,  however,  perfectly  colorless,  and  this  also  allows  of  an 
entire  series  of  special  applications.  A  few  masses  which 
can  be  prepared  from  viscoid  will  later  on  be  more  closely 
described. 

The  process  for  the  preparation  of  viscose  has  been  modi- 
fied by  several  technologists,  but  the  main  point  remains 
the  same  in  all  the  methods,  namely,  that  soda-cellulose  is 
first  prepared  and  then  converted  by  the  addition  of  carr 
bon  disulphide  into  viscoid,  which  is  dissolved  in  water. 

Cellulose  of  various  derivatives  is  used  as  raw  material 
for  the  preparation  of  the  viscose  solution.  Purified  cotton 
may  be  employed  just  as  well  as  cellulose  obtained  from 
wood,  and  cleaned  scraps  of  cotton  and  linen  fabrics  may 
also  be  utilized.  In  paper  mills,  viscose  is  especially  em- 
plo}*ed  for  sizing  finer  qualities  of  paper,  and  for  its  prep- 
aration so-called  half-stuff,  prepared  from  cotton  and  linen 
rags,  is  frequently  employed,  as  well  as  waste-paper  which 
must,  however,  be  entirely  free  from  wood-pulp. 

PREPARATION    OF    VISCOSE. 

For  experiments  on  a  smaller  scale  in  the  preparation  of 
viscose,  it  is  best  to  use  as  basis-materials  purified  cotton  or 
paper  free  from  mechanical  wood-pulp,  because  in  working 
other  materials,  the  assistance  of  disintegrating  and  mixing 
machinery  is  indispensable,  while  the  above-mentioned 
materials  can  be  readily  converted  into  soda-cellulose,  and 
the  latter  into  viscose. 

For  working  on  a  small  scale,  the  cotton  or  paper  is 
brought  into  a  large  rubbing  dish  and  concentrated  soda 
lye  poured  over  it,  the  latter  being  distributed  as  uniformly 


VISCOSE    AND    VISCOID.  121 

as  possible  throughout  the  mass  by  means  of  a  pestle. 
Enough  soda  lye  is  gradually  added  so  that  for  about  two 
parts  by  weight  of  dry  cellulose,  one  part  by  weight  of 
caustic  soda  is  used,  and  the  mixture  when  finished  con- 
tains in  round  figures,  six  parts  of  water.  When  the  entire 
quantity  of  caustic  soda  has  been  added,  the  dish  is  covered 
and  allowed  to  stand  for  some  time  so  that  any  fibres  which 
may  not  have  been  moistened,  can  come  in  contact  with  the 
caustic  soda.  The  mass  consisting  of  soda-cellulose  is  then 
quickly  pressed  out,  brought  into  a  flask  and  40  per  cent, 
of  its  weight  of  carbon  disulphide  poured  over  it.  The 
mass  soon  becomes  transparent  and  gelatinous  without, 
however,  becoming  fluid,  its  viscosity  being  so  great  that  it 
liquefies  only  when  a  sufficient  quantity  of  water  is  added. 
By  allowing  the  flask  to  stand  quietty,  the  particles  which 
have  remained  undissolved,  settle  gradually  on  the  bottom, 
and  the  supernatant  fluid  of  a  yellowish  color  becomes 
almost  entirely  clear.  This  fluid  consists  of  a  solution  of 
viscose  in  water. 

If  a  layer  of  this  solution  be  uniformly  distributed  upon 
a  glass  plate— in  the  manner  photographers  do  with  collo- 
dion— it  becomes  in  a  short  time  gelatinous  and  finally 
solid  and  odorless.  If  now  the  glass  plate  be  placed  in 
water,  changing  the  latter  several  times,  the  soda  is  dis- 
solved and,  after  drying,  a  perfectly  colorless  film  of  struct- 
ureless cellulose  can  be  drawn  off  from  the  glass  plate.  By 
mixing  certain  quantities'  of  viscose  solution  with  coloring 
substances  or  pulverulent  bodies,  experiments  on  a  small 
scale  may  also  be  made  for  the  production  of  masses  with 
fixed  properties. 

PREPARATION    OF   VISCOSE    ON    A    LARGE    SCALE. 

For  the  preparation  of  viscose  on  a  large  scale,  such  cellu- 
lose as  is  made  for  paper-manufacturing  purposes  is  gener- 
ally used,  a  short-fibered  product  with  fibres  0.059,  or  at 
the  utmost  0.079,  inch  in  length  being  generally  selected, 


122  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

because  experience  has  shown  that  long-fibered  cellulose 
requires  a  much  longer  time  for  conversion  into  soda- 
cellulose.  Since  the  process  proceeds  in  a  correct  manner 
only  when  the  soda  lye  shows  a  certain  degree  of  concen- 
tration, the  cellulose  should  contain  only  a  limited  amount 
of  water,  not  exceeding  50  per  cent.  Hence  the  content  of 
water  in  the  cellulose  has  to  be  accurately  established,  the 
quantities  of  further  additions  being  determined  thereby. 

The  operation  commences  with  the  comminution  of  the 
cellulose.  Small  disintegrators  were  formerly  used  for  this 
purpose,  but  at  the  present  time  the  cellulose  is  worked  in 
the  same  manner  as  for  blotting  paper,  the  knife  of  the 
hollander  being  so  set  as  to  obtain  a  product  of  as  short  a 
fibre  as  possible.  The  mass  coming  from  the  hollander  is 
as  far  as  possible  freed  from  water  in  a  centrifugal,  and  is 
then  spread  out  in  layers  and  left  until  it  is  air-dry. 

The  quantitative  proportions  between  cellulose  and  caus- 
tic soda  used  in  practice  vary  within  very  wide  limits. 
The  use  of  more  caustic  soda  than  is  absolutely  necessary 
for  the  formation  of  soda-cellulose  being  mere  waste,  the 
quantity  required  for  every  fresh  batch  of  cellulose  should 
be  accurately  determined  by  an  experiment  on  a  small 
scale,  because  in  working  many  hundred  pounds  of  cellu- 
lose one-half  per  cent,  more  or  less  of  caustic  soda  represents 
a  considerable  sum. 

The  proportions  generally  used  are  as  follows :  Air-dry 
cellulose,  25  to  33  parts ;  caustic  soda,  12.5  to  16 ;  water, 
52  to  55. 

The  caustic  soda,  which  should  always  be  used  in  the 
form  of  a  concentrated  solution,  is  mixed  with  the  cellulose, 
water  being  gradually  added,  because  the  at  first  highly 
concentrated  soda  solution  acts  more  rapidly  than  when  the 
entire  quantity  of  water  is  at  once  used.  It  may  here  be 
remarked  that  the  quantity  of  water  given  above  includes 
the  water  contained  in  the  air-dry  cellulose. 

The  commencement  of  the  formation  of  soda-cellulose  is 


VISCOSE    AND    VISCOID.  123 

recognized  by  the  behavior  of  the  mass,  it  swelling  up  very 
much,  and  a  considerable  increase  in  the  temperature  also 
takes  place.  When  the  mass  has  acquired  the  appearance 
of  crumbled  bread  it  is  an  indication  that  the  process  is 
finished. 

In  practice  the  preparation  of  soda-cellulose  is  effected  by 
two  different  methods,  and  every  manufacturer,  after  having 
once  adopted  one  of  them,  prefers  it  to  the  other.  However, 
both  are  perhaps  of  equal  value,  and  experience  and  practice 
play  no  doubt  an  important  part  in  obtaining  a  product  of 
suitable  properties.  According  to  one  of  the  methods  the 
cellulose  is  from  the  start  worked  with  soda  lye  of  the  proper 
degree  of  concentration,  while  according  to  the  other,  an 
excess  of  soda  lye  is  used,  which  later  on  is  removed. 

In  working  according  to  the  first  process,  the  cellulose  is 
treated  in  a  mill,  similar  in  construction  to  a  rag-engine 
used  in  the  manufacture  of  paper  for  breaking  up  half-stuff. 
The  cellulose  is  first  for  a  few  minutes  worked  by  itself  for 
the  purpose  of  loosening  it,  and  the  soda  lye  is  then  allowed 
to  run  in  in  small  portions  at  a  time,  a  fresh  quantity  being 
only  added  when  the  first  portion  has  been  absorbed.  If 
too  much  soda  lye  were  at  one  time  added  the  mass,  would 
become  very  slippery,  and  the  runner  of  the  mill  would 
slide,  instead  of  rolling,  over  it. 

When  the  total  quantity  of  soda  lye  has  been  added  the 
mill  is  kept  in  motion  until  the  termination  of  the  process 
is  indicated  by  the  mass  becoming  crummy.  Since  the 
mass  may  contain  harder  lumps,  which  might  cause  the 
formation  of  a  non-homogeneous  product,  it  is  passed,  after 
being  taken  from  the  mill,  through  a  sieve  with  meshes  not 
over  0.19  to  0.23  inch  wide.  The  sifted  mass  is  immediately 
brought  into  the  storage  vessels,  which  must  be  closed  air- 
tight, though  it  may  also  be  at  once  used  for  the  prepara- 
tion of  viscose. 

For  the  preparation  of  soda-cellulose  according  to  the 
other  method,  in  which  soda  lye  in  excess  is  used,  the  cellu- 


124  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

lose  is  first  mixed  with  about  ten  times  the  quantity  of  soda 
lye  of  15  to  18  per  cent.  The  lye  is  allowed  to  act  until 
the  operation  is  finished,  the  portion  of  it  which  has  not 
been  absorbed  is  discharged,  and  the  mass  is  treated  in  a 
centrifugal,  a  certain  quantity  of  lye  being  thereby  regained. 
By  simply  mixing  the  cellulose  with  the  soda  lye,  lumps 
are  frequently  formed  in  the  mass  in  consequence  of  the 
increase  in  volume  which  takes  place,  and  the  soda-cellulose 
after  coming  from  the  centrifugal  has  to  be  especially  com- 
minuted and  passed  through  a  sieve. 

SODA-CELLULOSE. 

In  storing  soda-cellulose  prepared  according  to  one  of  the 
processes  described  above,  it  will  sometimes  be  observed 
that  it  becomes  heated  to  quite  a  high  degree.  This  phe- 
nomenon can  only  be  explained  by  assuming  that  the  for- 
mation of  soda-cellulose  is  only  incompletely  effected  in  the 
apparatus  used  for  the  purpose,  and  that  it  is  gradually 
effected  in  the  storage  vessels.  However,  by  this  process  a 
certain  quantity  of  heat  is  liberated,  which  by  reason  of 
the  wood  of  the  barrels  used  for  storage  being  a  bad  con- 
ductor, is  kept  together. 

Since  the  quality  of  the  soda-cellulose  is  impaired  by  this 
development  of  heat,  and  there  may  be  even  danger  of  a 
fire  breaking  out  in  consequence  of  it,  certain  precautions, 
given  below,  should  be  observed  in  storing  soda-cellulose. 

The  main  point  in  the  manufacture  of  soda-cellulose  is  to 
have  the  entire  process  finished  as  rapidly  as  possible,  soda- 
cellulose  being  a  body  which  absorbs  with  avidity  carbonic 
acid  from  the  air,  and  to  bring  the  product  immediately 
into  the  storage  vessels,  closing  the  latter  air-tight. 

STORING    SODA-CELLULOSE. 

Soda-cellulose  being  a  combination  of  but  slight  con- 
stancy, only  such  a  quantity  should,  as  a  rule,  be  prepared 
in  one  operation  as  can  be  worked  into  viscose  in  three  or 


VISCOSE    AND    VISCOID.  125 

four  days,  experience  having  shown  that  a  very  thickly- 
fluid  viscose  cannot  be  obtained  from  soda-cellulose  which 
has  undergone  changes  by  long  storing,  the  product  in  this 
case  possessing  but  little  viscosity. 

The  injurious  changes  soda-cellulose  undergoes  appear 
the  more  quickly  the  higher  the  temperature  is  to  which  it 
is  exposed.  Hence  means  should  be  provided  in  every 
factory  by  which  the  product  can  be  kept  in  an  unchanged 
state  from  the  moment  it  leaves  the  mill  and  has  been 
passed  through  the  sieve.  Instead  of  bringing  the  pro- 
duct into  a  wooden  vessel,  it  is  allowed  to  fall  into  a  large 
sheet-iron  vessel  which  is  surrounded  with  ice.  When 
this  vessel  has  been  filled  with  the  sifted  mass,  a  ther- 
mometer is  pushed  into  the  center  of  the  latter,  and  the 
vessel  closed  with  a  well-fitting  lid.  Soda-cellulose  being  a 
bad  conductor  of  heat,  some  time  is  required  for  the  mass 
to  cool  throughout,  and  it  must  be  allowed  to  stand  until 
the  thermometer  indicates  a  temperature  of  41°  to  43°  F. 
The  mass  is  then  quickly  packed  into  the  storage  barrels 
and  the  latter  are  placed  in  a  cool  cellar,  best  in  an  ice- 
house. The  expense  of  the  ice  required  is  slight  in  com- 
parison to  the  loss  incurred  by  the  spoiling  of  a  quan- 
tity of  the  product.  In  storing  the  soda-cellulose  at  such 
a  low  temperature  larger  vessels  may  also  be  used.  How- 
ever, in  storing  the  product  at  a  higher  temperature,  the 
use  of  smaller  barrels  of  about  220  Ibs.  capacity  would  at 
all  events  appear  not  advisable,  since,  as  is  well  known, 
the  heat  from  the  outside  acts  more  rapidly  in  a  smaller 
vessel  than  in  a  larger  receptacle. 

Comparative  experiments  have  shown  that  soda-cellulose 
stored  in  an  ice-house  remained  unchanged  after  two 
months,  but  its  stability  decreased  with  every  degree  of 
heat.  A  maximum  temperature  of  50°  to  53.6°  F.  would 
appear  to  be  most  suitable  for  the  storage  room,  and  if  arti- 
ficial cooling  is  not  to  be  applied,  the  cold  season  of  the 
year  is  best  adapted  for  the  manufacture  of  soda-cellulose. 


126  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

However,  in  many  countries  the  manufacturer  is,  even  in 
the  cold  season,  subject  to  the  caprices  of  the  weather,  and 
it  is  therefore  advisable  to  combine  a  cooling  plant  with  a 
viscose  factory.  Soda-cellulose,  which  was  kept  at  68°  F. — 
the  ordinary  temperature  of  a  room — became,  as  a  rule,  so 
changed  in  60  to  70  hours  that  it  could  no  longer  be  used. 

As  regards  the  products  formed  by  the  decomposition  of 
soda-cellulose  in  consequence  of  the  action  of  too  high  a 
temperature,  the  appearance  of  acetic  acid  (formic  acid  ?), 
lactic  acid  and  acetyl-lactic  acid  has  been  established.  These 
combinations,  however,  can  only  appear  with  the  complete 
decomposition  of  the  cellulose.  Hence  it  appears  probable 
that  the  alteration  of  the  soda-cellulose  commences  with  a 
transposition  inside  the  molecule  of  the  cellulose,  the  conse- 
quence being  that  a  large  part  of  the  substance  is  no  longer 
soda-cellulose,  and  hence  cannot  form  the  combination  to 
which  the  term  viscose  has  been  applied. 

The  unpleasant  observations  made  in  working  soda-cellu- 
lose in  which  alteration  has  already  commenced  are  of  vary- 
ing nature,  but  the  fluid  lacks  chiefly  the  great  viscosity 
and  adhesive  power  which  are  its  characteristic  properties. 
The  cellulose  recovered  from  such  a  thin  solution  possesses 
but  little  strength,  and  is  so  brittle  that  it  can  scarcely  be 
worked. 

PREPARATION  OF  VISCOSE. 

Viscose  is  formed  by  simply  bringing  together  at  the 
ordinary  temperature  soda-cellulose  with  carbon  disulphide, 
the  process  taking  place  the  more  rapidly  the  more  intimate 
the  contact  between  the  two  bodies.  Chemically  the  com- 
bination formed  is  cellulose  sulphocarbonate.  It  is  readily 
soluble  in  water  and  on  exposure  to  the  air  is  decomposed 
at  the  ordinary  temperature,  cellulose  in  the  form  of  a  color- 
less and  structureless  mass  being  separated.  At  a  higher 
temperature  decomposition  progresses  with  great  rapidity. 

In  preparing  viscose  it  must  be  borne  in  mind  that  car- 


VISCOSE    AND    VISCOID.  127 

bon  disulphide  is  a  very  volatile  substance — its  boiling 
point  being  at  118.4°  F. — and  vessels  which  can  be  closed 
absolutely  air-tight  have  to  be  used.  Carbon  disulphide 
frequently  contains  small  quantities  of  sulphur  in  solution 
and  as  this  would  have  an  injurious  effect  upon  metallic 
vessels,  apparatus  entirely  constructed  of  wood  should  be 
employed. 

The  most  suitable,  and  at  the  same  time  the  most  simple, 
apparatus  for  the  preparation  of  larger  quantities  of  viscose 
is  a  revolving  barrel  with  quite  a  large  bung-hole,  which 
can  be  securely  closed  with  a  screw-cover.  In  place  of  a 
revolving  barrel,  a  stationary  barrel  may  also  be  used.  The 
contents  are  mixed  by  means  of  a  stirfer  consisting  of  a 
shaft  with  shovel-like  paddles  with  which  the  barrel  is  fur- 
nished. 

The  proportion  between  soda  lye  and  carbon  disulphide 
is,  by  the  way,  10  to  1.  For  100  parts  of  soda-cellulose  10 
parts  of  carbon  disulphide  are  used,  though  a  small  excess 
of  the  latter  is  of  no  importance.  When  both  the  sub- 
stances have  been  brought  into  the  apparatus,  the  latter  is 
securely  closed  and  set  in  motion,  being  thus  kept  uninter- 
ruptedly until  the  formation  of  the  combination  is  com 
plete.  The  time  necessary  for  this  purpose  depends  largely 
on  the  temperature ;  three  hours  being,  as  a  rule,  required 
with  a  temperature  of  60°  F.,  while  with  one  of  77°  to  86° 
F.,  the  formation  of  the  combination  may  be  complete  in 
one  hour. 

The  cellulose  sulphocarbonate  forms  a  loose  mass,  differ- 
ing in  appearance  from  soda-cellulose  only  by  its  pale  yel- 
low color.  When  brought  in  contact  with  water  it  should 
gradually  be  completely  dissolved.  If  any  flakes  remain 
undissolved,  it  may  be  due  to  two  causes,  one  of  them  being 
that  all  the  cellulose  has  not  been  converted  into  soda- 
cellulose,  and  the  other,  that  an  insufficient  quantity  of 
carbon  disulphide  has  been  used,  or  that  it  has  acted  for 
too  short  a  time.  In  the  first  case,  the  mass  cannot  be  im- 


128  CELLULOSE.  AND    CELLULOSE    PRODUCTS. 

proved,  but,  in  the  second,  an  experiment  may  be  made  by 
continuing  the  manipulation  in  the  revolving  barrel  with 
the  addition  of  a  certain  quantity  of  carbon  disulphide. 

When  the  proportions  have  been  correctly  chosen,  a  small 
excess  of  carbon  disulphide  remains,  as  a  rule,  behind. 
This  may  be  recovered  by  attaching  to  the  hollow  shaft  of 
the  barrel  a  pipe  ending  in  a  coil  which  terminates  in  a 
vessel  filled  with  ice.  A  small  suction  pipe  is  placed  on 
the  lower  end  of  this  ice  vessel.  The  other  end  of  the  hol- 
low shaft  of  the  revolving  barrel  is  furnished  with  a  small 
cock.  This  cock  is  opened  and  the  suction  pump  set  in 
motion  while  the  barrel  is  slowly  revolving,  a  current  of  air 
being  thus  sucked  through  the  contents  of  the  barrel 
whereby  the  excess  of  carbon  disulphide  is  evaporated. 
The  vapors  on  coming  in  contact  with  the  ice  are  con- 
densed, and  ice  water  and  carbon  disulphide  run  off  into  a 
collecting  vessel  placed  at  the  lower  end  of  the  ice-holder. 

PREPARATION  OF  VISCOSE  SOLUTION. 

For  this  purpose  the  contents  of  the  revolving  barrel  are 
brought  into  a  closed  vessel  which  is  furnished  with  a 
vigorously-acting  stirring  contrivance,  and,  after  setting  the 
latter  in  motion,  water  in  small  quantities  is  allowed  to  run 
in.  Immediately  after  the  first  portions  of  water  have 
been  admitted,  the  mass  commences  to  swell  up  very  much, 
and  would  in  a  short  time  acquire  such  a  degree  of  vis- 
cosity as  to  impede  the  motion  of  the  stirrer.  Hence  more 
water  is  allowed  to'run  in  until  the  quantity  of  it  admitted 
amounts  to  1  \  times  the  weight  of  the  soda-cellulose  brought 
into  the  apparatus. 

The  stirrer  is  kept  in  motion  until  solution  is  complete, 
when  the  viscose  is  immediately  brought  into  the  vessels  in 
which  it  is  to  be  stored  or  shipped.  Viscose  should  as  far 
as  possible  be  protected  from  the  access  of  air,  being  rap- 
idly decomposed  on  coming  in  contact  with  it.  Viscose 
solution  which  is  immediately  to  be  used  in  factories  where 


VISCOSE  AND  VISCOID.  129 

it  has  been  prepared,  may  be  kept  in  an  open  vessel  of  wood 
or  zinc-sheet.  A  layer  of  water  is  carefully  poured  upon  it 
so  that  no  mixing  of  the  two  fluids  takes  place  ;  this  layer 
of  water  protecting  the  viscose  from  becoming  decomposed. 
When  viscose  solution  is  allowed  to  stand  open,  a  thin  film 
of  cellulose  forms  in  a  short  time  on  the  surface,  and  this 
has  to  be  removed  when  the  viscose  is  to  be  used. 

STORING    VISCOSE. 

Since  viscose  is  rapidly  decomposed  by  the  access  of  air, 
as  well  as  at  a  higher  temperature,  special  precautionary 
measures  have  to  be  taken  to  prevent  decomposition  when 
larger  quantities  of  it  are  to  be  stored.  As  is  the  case  with 
soda-cellulose,  these  precautionary  measures  consist  in  shut- 
ting out  the  access  of  air,  and  keeping  the  storage-room  at  a 
low  temperature. 

The  most  simple  plan  is  to  store  the  viscose  in  a  sheet- 
zinc  cylinder  provided  around  its  upper  edge  with  a  gutter, 
into  which  fits  the  1}  to  2  inches  deep  rim  of  a  sheet-zinc 
lid.  The  vessel  having  been  filled,  the  lid  is  placed  in  the 
gutter  and  the  latter  filled  with  water,  thus  forming  a  kind 
of  hydraulic  joint,  which  renders  the  access  of  air  to  the 
contents  of  the  cylinder  impossible. 

The  stability  of  the  viscose  is  the  greater  the  lower  the 
temperature  of  the  room  in  which  it  is  stored.  In  rooms 
having  a  temperature  of  77°  F.  or  more,  decomposition 
takes  place  very  rapidly ;  at  the  ordinary  temperature 
of  a  room  viscose  cannot  be  kept  longer  than  5  or  6  days 
without  undergoing  a  change,  and  stability  for  two  weeks 
can  only  be  counted  upon  with  a  temperature  below  50°  F. 

If,  however,  viscose  solutions  are  stored  in  a  room  the 
temperature  of  which  is  kept,  by  artificial  cooling,  not  much 
above  the  freezing  point  of  water,  the  viscose  can  be  kept 
in  a  perfectly  unchanged  state  for  a  number  of  weeks.  In- 
dependent of  the  assurance  of  preserving  the  viscose  in  an 
unchanged  state,  storing  it  at  a  low  temperature  offers  a 
9 


130  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

great  advantage  in  working  the  material.  The  temperature 
of  the  viscose  when  taken  from  the  storage  vessel  is  of  course 
quite  low,  and  as  it  becomes  gradually  higher  in  the  normal 
warmth  of  the  work-room,  there  is  no  difficulty  whatever  in 
working  it  at  the  degree  of  heat"  best  adapted  for  the  work 
in  hand. 

The  shipping  of  viscose,  especially  during  the  warm  sea- 
son of  the  year,  is  connected  with  many  difficulties,  which 
can  only  be  overcome  by  special  precautionary  measures. 
Viscose  is  shipped  in  closed  sheet-zinc  vessels,  and  when  the 
latter  are  in  a  hot  summer  day  forwarded  by  railroad,  there 
is  great  danger  as  regards  the  stability  of  the  product,  since 
the  temperature  of  freight  cars  exposed  to  the  sun  frequently 
reaches  95°  F.  or  more.  Hence  the  viscose,  cooled  down  to 
a  low  temperature,  should'  be  shipped  by  fast  freight,  and 
the  vessels  containing  it  be  protected  as  much  as  possible 
from  heating  by  wrapping  them  in  wet  cloths. 

PROPERTIES  OF  VISCOSE  SOLUTIONS. 

The  commencement  of  the  decomposition  of  a  viscose 
solution  is  first  of  all  recognized  by  the  mass,  at  first  only 
viscid  and  of  about  the  consistency  of  a  gum  solution,  be- 
coming thicker  and  acquiring  the  consistency  of  a  warm 
glue  solution  at  the  beginning  of  coagulation.  As  decom- 
position progresses  the  mass  assumes  the  consistency  of 
jelly.  By  taking  it  in  hand  at  the  right  time,  the  mass 
may  be  restored  to  a  useful  condition  by  adding  a  suitable 
quantity  of  water,  thus  making  it  again  more  thinly-fluid. 

It  is  probable  that  changes  constantly  take  place  even  in 
a  perfectly  available  viscose  solution,  as  shown  by  the  be- 
havior of  viscose  when  exposed  in  a  thin  layer  to  the  air. 
In  many  cases  decomposition  simply  takes  place  by  vapors 
of  carbon  disulphide  escaping  from  the  mass,  which  con- 
stantly becomes  more  thickly-fluid,  and  finally  nothing  but 
cellulose  remains  behind. 

In  other  cases  it  will,  however,  be  noticed  that  sulphur- 


VISCOSE    AND    VISCOID.  131 

etted  hydrogen  is  evolved,  and  that  the  mass  contains  con- 
siderable quantities  of  sodium  carbonate  as  well  as  sul- 
phides and  trithiocarbonate.  The  appearance  of  these 
combinations  can  only  be  explained  by  the  decomposition, 
by  the  action  of  the  alkali,  of  a  portion  of  the  carbon  disul- 
phide  present. 

The  decomposition  of  the  viscose  is  very  much  influenced 
by  the  temperature  at  which  it  takes  place.  Viscose  solu- 
tion exposed  upon  a  glass  plate  to  a  temperature  of  but  a 
few  degrees  above  the  freezing  point  is  changed  very  slowly  ; 
the  mass  constantly  acquires  greater  consistence  and  a  solid, 
structureless  film  consisting  of  cellulose  remains  finally 
behind.  The  higher  the  temperature,  the  shorter  the  time 
in  which  decomposition  takes  place  and  at  104°  F.,  it  pro- 
ceeds with  great  rapidity.  When  the  temperature  rises 
above  122°  F.,  a  homogeneous,  coherent  mass  is  no  longer 
obtained,  but  one  which  here  and  there  shows  white  spots 
which  are  produced  by  numerous  small  bubbles.  At  this 
high  temperature  decomposition  takes  place  with  such 
rapidity  that  the  vapors  evolved  can  no  longer  escape  from 
the  mass  on  account  of  its  viscosity,  but  are  retained  in  it 
like  air-bubbles  in  rapidly  freezing  ice.  At  a  still  higher 
temperature,  for  instance,  pouring  the  solution  upon  a 
highly  heated  plate,  decomposition  of  the  viscose  takes 
place  almost  instantly,  a  mass  of  a  very  porous,  spongy 
nature  being  obtained. 

In  many  cases,  for  instance,  in  using  viscose  for  sizing 
paper,  it  might  be  desirable  for  decomposition  to  take  place 
more  rapidly  at  the  ordinary  temperature  than  usually 
is  the  case,  and  this  may  be  done  by  replacing  the  soda  in 
the  viscose  by  ammonia.  The  decomposition  of  viscose 
prepared  in  this  manner  takes  place  at  a  much  lower  tem- 
perature than  that  of  soda-viscose,  and  carbon  disulphide 
and  ammonia  escape  in  abundance  from  the  decomposing 
mass.  As  previously  mentioned,  the  behavior  of  viscose  in 
decomposing  depends  on  the  temperature  and  its  age,  and 


132  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

only  by  long,  practical  experience  is  it  possible  to  judge 
from  the  start  of  its  action  in  this  respect.  Hence  to  avoid 
disagreeable  occurrences  it  is  recommended  to  test  a  small 
quantity  of  every  fresh  viscose  to  be  worked  as  to  its  be- 
havior, and  to  arrange  the  course  of  the  work  accordingly. 

CONVERSION    OF    VISCOSE    INTO    VISCOID. 

When  a  0.15-  to  0.19-inch-deep  layer  of  a  viscose  solution 
in  a  vessel  is  exposed  to  a  temperature  not  exceeding  40°  F., 
a  thin  film  is  first  formed,  and,  by  exercising  care,  can  be 
lifted  off.  If  this  film  be  brought  into  water  it  redissolves, 
and  therefore  it  consists  evidently  of  a  combination  having 
some  resemblance  to  viscose,  though  it  appears  in  a  solid 
form.  If,  however,  this  film  be  for  some  time  exposed  to 
the  air  it  loses  its  solubility  in  water,  but  swells  up  in  it  to 
a  jelly-like  mass.  If  finally  it  be  exposed  for  from  half  an 
hour  to  an  hour  to  a  temperature  of  212°  F.,  it  has  become 
entirely  indifferent  to  water  and  behaves  towards  it  like  a 
film  of  nitro-cellulose. 

Except  for  the  production  of  very  thin  films  and  threads, 
viscose  is  seldom  used  by  itself.  For  the  preparation  of 
thicker  plates  from  viscoid — this  term  being  applied  to  con- 
gealed viscose — a  special  method  has  to  be  adopted  in  order 
to  obtain  a  perfect  product.  First  of  all  it  is  necessary  to 
know  how  thick  the  plates  will  be  which  can  be  obtained 
from  a  viscose  layer  of  determined  thickness  by  its  conver- 
sion into  viscoid,  and  this  is  ascertained  by  a  preliminary 
experiment  on  a  small  scale.  For  the  preparation  of  thick 
plates  or  blocks,  sheet-zinc  vessels  of  appropriate  depth  are 
used  and  filled  with  viscose.  The  vessels  are  then  exposed 
in  a  room  perfectly  free  from  dust  to  a  uniform  temperature 
of  95°  to  104°  F.  until  the  mass  remaining  in  them  has 
acquired  the  requisite  quality.  In  order  not  to  be  incon- 
venienced by  the  vapors  of  carbon  disulphide  and  other 
products  of  decomposition  escaping  from  the  mass,  it  is 
advisable  to  place  the  vessel  in  a  box  furnished  with  a  pipe 


VISCOSE    AND    VISCOID.  133 

entering  a  chimney,  and  to  keep  the  temperature  of  the  box 
uniformly  at  the  above-mentioned  degree,  by  a  few  heating 
pipes. 

When  a  solid  mass  has  been  formed  it  is  removed  from 
the  vessel  and  for  some  time  heated  at  212°  F.  Viscoid 
being  a  bad  conductor,  this  heating  must  be  continued  the 
longer  the  thicker  the  plates  are ;  at  any  rate  it  must  be 
continued  till  the  plates  when  dipped  in  water  no  longer 
swell  up. 

The  plates  are  then  laid  in  clean  water,  by  which  the 
salts  contained  in  them  are  slowly  dissolved,  the  water 
being  renewed  so  long  as  soluble  substances  from  the  vis- 
coid  are  absorbed  by  it.  When  the  work  has  been  care- 
fully done  the  viscoid  plates  present  the  appearance  of 
transparent  glass.  If  the  plates  show  here  and  there  dull 
specks  or  white  opaque  spots,  it  is  an  indication  of  too  high 
a  temperature  having  been  used  in  drying  up  the  viscose, 
and  that  the  mass  is  interspersed  with  small  bubbles. 

BEHAVIOR    OF    VISCOSE    TOWARDS    METALLIC    SALTS. 

When  a  viscose  solution  is  brought  together  with  a  me- 
tallic salt,  reciprocal  decomposition  takes  place,  the  metallic 
oxide  combining  with  the  cellulose  and  the  sulphocar- 
bonate,  while  the  soda  fixes  the  acid  of  the  metallic  salt. 
The  new  combinations  thus  formed  have  not  yet  been 
sufficiently  investigated  as  to  their  availability  in  practice, 
though  a  few  of  them  have  found  practical  application  in 
the  manufacture  of  paper.  By  mixing  magnesium  sulphate 
with  viscose,  magnesium-viscose  and  sodium  sulphate  are 
obtained,  and  as  both  these  salts  are  readily  soluble  in 
water,  no  precipitation  takes  place  after  adding  the  magne- 
sium sulphate.  Magnesium-viscose  possesses  the  property 
of  decomposing  with  still  greater  rapidity  than  soda-viscose, 
which  makes  it  very  valuable  for  certain  purposes,  especially 
for  sizing  paper ;  the  sodium  sulphate  adhering  to  the  de- 
composed mass  being  a  readily  soluble  salt  can  without 
trouble  be  removed  from  the  paper  mass. 


134  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

By  adding  to  a  viscose  solution  the  solution  of  a  salt  of  a 
heavy  metal,  insoluble  viscose  of  the  metal  added  is 
formed.  With  the  exception  of  the  zinc  combination,  which 
is  used  for  sizing  in  the  manufacture  of  paper,  none  of  these 
combinations  has  become  of  technical  importance. 

The  proportional  quantities  of  the  bodies  which  are  added 
to  sodium-viscose  for  the  purpose  of  obtaining  other  varie- 
ties of  viscose,  vary  according  to  the  object  which  the 
preparations  in  question  are  to  serve.  Thus,  for  instance, 
in  paper  mills  9  parts  ammonium  sulphate,  or  15  parts 
magnesium  sulphate,  or  18  parts  crystallized  zinc  sulphate 
are  used  for  every  100  parts  of  a  10  per  cent,  soda-viscose. 

PREPARATION  OF  VISCOSE  ACCORDING  TO  CROSS. 

According  to  a  process  recently  patented  by  F.  Cross,  the 
quantity  of  caustic  soda  required  for  the  preparation  of  vis- 
cose can  be  reduced  one-half  by  treating  the  cellulose  to  be 
worked  previous  to  submitting  it  to  the  action  of  the  alkali, 
with  dilute  acids,  at  a  temperature  of  between  212°  and  284° 
F.  This  is  of  great  advantage,  because  on  the  one  hand, 
with  the  use  of  large  quantities  of  caustic  soda  the  cost  of 
producing  the  article  is  considerably  greater,  and,  on  the 
other,  the  large  content  of  alkali  and  sulphur  in  viscose 
prepared  according  to  the  older  method  is  an  impediment 
to  its  use  for  many  purposes. 

The  preparation  of  cellulose  according  to  this  process 
may  be  effected  in  various  ways.  According  to  one  method 
the  fibrous  cellulose  is  treated  as  follows :  Paper  pulp,  half- 
stuff,  rags,  waste  paper,  etc.,  are  for  a  few  hours  boiled  with 
dilute  (2  per  cent.)  hydrochloric  or  sulphuric  acid  ;  or  the 
fluid  is  brought  to  the  boiling  point  by  itself  when  the  cel- 
lulose is  introduced,  boiling  being  constantly  kept  up,  and 
allowed  to  remain  in  the  fluid  until  it  has  been  converted 
into  the  brittle  modification.  According  co  another  method, 
the  cellulose  is  completely  saturated  at  the  ordinary  tem- 
perature with  dilute  (2  per  cent.)  hydrochloric  acid.  The 


VISCOSE  AND  VISCOID.  135 

I    •  j 

excess  of  hydrochloric  acid  is  then  removed  by  treating  the 
mass  in  a  centrifugal,  and  the  cellulose  is  completely  dried 
at  a  temperature  of  between  140°  arid  176°  F.,  care  being 
taken  that  drying  is  uniformly  effected.  The  transition  of 
the  cellulose  to  the  brittle  modification  then  takes  place 
during  drying. 

According  to  a  third  method  given  by  Cross,  the  cellu- 
lose is  for  a  short  time  treated  with  dilute  (1  per  cent.)  sul- 
phuric acid  in  a  digester  under  high  pressure  at  a  tempera- 
ture of  between  212°  and  284°  F.  In  place  of  dilute 
sulphuric  acid,  dilute  hydrochloric  acid  containing  but  J 
per  cent,  of  acid  may  also  be  used.  The  quantity  of  acid 
used  should  amount  to  five  times  the  weight  of  the  cellulose 
to  be  worked.  The  mass  coming  from  the  digester  is  freed 
from  the  acid  fluid  by  washing,  and  pressed  to  reduce  its 
content  of  water  to  between  50  and  40  per  cent. 

The  most  advantageous  proportional  quantities  of  caustic 
soda  and  water  to  be  used  for  the  cellulose  thus  prepared 
are  within  the  following  limits :  Cellulose  40  to  50,  caustic 
soda  10  to  12,  water  50  to  38  per  cent. 

The  soda  lye  is  used  in  accordance  with  the  content  of 
water  in  the  cellulose  to  be  worked,  and  the  further  manip- 
ulation of  mixing  to  soda-cellulose  is  generally  effected  in 
a  crushing  mill  or  other  grinding  contrivance,  the  operation 
being  continued  until  the  mass  is  perfectly  homogeneous. 
The  conversion  of  the  soda-cellulose  into  viscose,  and  of  the 
latter  into  viscoid,  does  not  differ  from  the  method  previously 
described. 

PREPARATION    OF    VISCOSE    ACCORDING    TO    SEIDEL. 

H.  Seidel's  process  for  the  preparation  of  viscose  differs 
but  little  from  the  one  just  described.  According  to  the 
inventor's  statements,  100  parts  of  sulphite-cellulose  are  for 
a  few  hours  placed  in  dilute  (1  per  cent.)  hydrochloric 
acid,  the  mass  is  then  squeezed  out  and  rinsed  in  water. 
It  is  then  brought  into  intimate  contact  with  a  solution  of 


136  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

40  parts  of  caustic  soda  in  100  parts  of  water,  and  left  to 
itself  in  a  closed  vessel  for  three  days.  One  hundred  parts 
of  carbon  disulphide  are  then  brought  into  the  vessel  and 
distributed  by  stirring,  when  the  mass  is  again  allowed  to 
repose  for  12  hours.  A  yellow-colored  solution  is  formed 
from  which  the  viscose  may  be  precipitated  by  alcohol  or 
common  salt  solution. 

Viscose  prepared  from  sulphite-cellulose  dissolves  with 
somewhat  greater  difficulty,  but  has  the  advantage  of  being 
lighter  in  color  than  other  varieties,  and  can  even  be  ob- 
tained entirely  colorless.  It  is  less  suitable  for  the  prepar- 
ation of  plastic  masses,  but  is  remarkably  well  adapted  for 
sizing  paper. 

According  to  Seidel,  transparent  plates  of  viscose  are  ob- 
tained from  cotton  by  treating  cotton  fabrics,  according  to 
the  process  just  given,  up  to  the  period  at  which  the  addi- 
tion of  carbon  disulphide  is  to  be  made.  Instead  of  adding 
the  latter,  the  fabrics  are  hung  in  a  room  the  atmosphere 
of  which  is  saturated  with  carbon  disulphide  vapors,  allow- 
ing them  to  remain  for  twelve  hours.  The  rinsed  fabric  is 
stretched  smoothly  upon  a  glass  plate,  exposed  for  two  days 
to  the  air,  then  completely  dried  in  a  drying  closet,  and 
finally  placed  in  dilute  hydrochloric  or  acetic  acid. 

According  to  this  process,  plates  are  obtained  which  have 
the  appearance  of  parchment,  and  by  heating  to  212°  F., 
become  so  plastic  that  they  may  be  given  any  desired 
shape.  They  can  be  bleached  with  chloride  of  lime  and 
then  form  a  perfectly  colorless  mass,  which,  when  colored, 
retains  its  transparency.  It  may  here  be  remarked  that 
the  process  above  described  would  seem  to  be  of  but  little 
practical  importance  since  viscoid  plates  can  be  prepared  in  a 
much  simpler,  and  at  the  same  time  cheaper,  manner  from 
ordinary  viscose  by  spreading  a  somewhat  thicker  layer  of 
the  latter  upon  a  glass  plate  provided  with  a  rim  of  appro- 
priate height,  detaching  the  smooth  plate  from  the  glass 
plate,  and  treating  it  further  in  the  usual  way.  The  use  of 


VISCOSE    AND    VISCOID.  337 

cellulose  in  the  form  of  cotton  offers  no  advantage,  but  con- 
siderably increases  the  cost  of  production. 

The  process  above  described  may,  however,  be  utilized  to 
advantage  for  giving  a  loosely-woven,  thin  tissue  the  ap- 
pearance of  a  close  and  firm  fabric.  For  this  purpose  the 
washed  and  dried  tissue  is  unwrapped  from  a  roll  into  a 
vessel  containing  the  soda  lye,  remaining  in  it  for  several 
days  so  that  a  considerable  quantity  of  soda-cellulose  may 
be  formed. 

The  tissue  is  then  freed  from  the  greater  portion  of 
adhering  fluid  by  subjecting  it  to  strong  pressure  between 
two  rolls.  It  is  next  loosely  hung  up  in  a  chamber,  the 
door  and  windows  of  which  can  be  closed  air-tight.  A 
shallow  vessel  filled  with  carbon  disulphide  is  placed  upon 
the  floor  of  the  chamber  and  the  latter  closed  air-tight. 
The  tissue  is  allowed  to  remain  in  the  chamber  until  the 
quite  dark  yellow  color  it  acquires  by  the  action  of  the  car- 
bon disulphide  remains  constant. 

The  chamber  is  then  opened,  thoroughly  aired  and  the 
tissue  is  removed  when  it  has  again  become  white  and  per- 
fectly dry.  It  is  then  taken  through  a  bath  of  dilute  (2  to 
3  per  cent.)  hydrochloric  acid,  washed  and  dried  in  a 
stretched  state,  this  being  necessary  as  otherwise  it  would 
shrink  very  much. 

Tissues  thus  treated  appear  nearly  twice  as  thick  as  orig- 
inally, feel  firm  to  the  touch,  and  possess  remarkable 
strength.  These  phenomena  may  be  explained  by  the 
change  the  separate  fibres  of  which  each  thread  consists 
have  undergone.  Every  fibre  on  its  surface  and  to  within 
a  certain  depth  has  been  converted  into  viscose  which  pen- 
etrates the  entire  mass  like  varnish.  The  tissue  taken  from 
the  carbon-disulphide  chamber  acquires,  when  moistened 
with  water,  a  quality  reminding  one  of  a  thoroughly  soaked 
animal  skin.  When  the  viscose  is  again  decomposed  the 
separated  cellulose  cements  the  finest  fibres  of  the  threads 
most  intimately  together,  and  this  explains  the  compact  ap- 


OF  THE 

UNIVERSITY 

OF 


138  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

pearance,  firm  feel,  and  great  strength  of  the  tissues  thus 
treated. 

PREPARATION    OF  CHEMICALLY-PURE    CELLULOSE-SULPHO- 
CARBONATE  (VISCOSE). 

Viscose  prepared  according  to  the  ordinary  .method  is  not 
a  pure  product  consisting  solely  of  the  combination  cellu- 
lose-sulphocarbonate,  but  always  contains  certain  quantities 
of  sodium  carbonate,  thiocarbonic  acid  and  carbon  disul- 
phide.  According  to  the  process  of  the  Viscose  Syndicate 
Limited,  it  can  be  freed  from  these  bodies  by  treating  the 
raw  product  with  weak  acids — lactic,  formic  or  acetic  acid 
—in  excess,  whereby  the  viscose  is  not  changed,  but  the 
above-mentioned  foreign  bodies  are  rendered  harmless.  The 
fluid  is  then  mixed  with  a  water-withdrawing  body,  such  as 
alcohol  or  common  salt  solution,  and  entirely,  pure  viscose 
which  separates  as  a  mass  of  leathery  appearance,  is  thus 
obtained.  The  product  is  again  washed  with  dilute  alcohol 
or  common  salt  solution,  and  dried. 

Pure  viscose  obtained  in  the  above-described  manner,  is 
a  neutral,  colorless  and  odorless  mass,  which  rapidly  dis- 
solves in  water  without  leaving  a  residue,  and  is  especially 
well  adapted  for  sizing  paper  and  fabrics. 

USES  OP  VISCOSE. 

Viscose,  or  viscoid  prepared  from  it,  is  already  used  to  a 
considerable  extent  in  various  industries,  and  it  may  be 
supposed  that  both  these  substances  will  find  various  tech- 
nical applications.  Viscoid,  as  previously  explained,  is 
simply  pure  cellulose,  and  it  being  in  a  certain  measure 
available  in  a  fluid  state  in  viscose,  it  is  possible  to  obtain 
the  cellulose  in  a  solid  form  and  to  give  the  article  thus  ob- 
tained any  desired  color. 

Quite  bulky  bodies  can  be  prepared  from  viscose,  and 
any  desired  pulverulent  substances  may  be  incorporated 
with  the  mass  as  it  becomes  solid,  so  that  the  articles  pro- 


VISCOSE    AND    VISCOID.  139 

duced  in  this  manner  resemble,  as  regards  their  appearance 
and  partially  their  properties  also,  horn,  ivory,  wood  or 
stone.  In  the  same  manner  transparent  plates  or  very  thin 
leaves  may  be  prepared  from  viscoid,  or  they  may  be  ob- 
tained in  the  form  of  exceedingly  fine  threads  well  adapted 
for  spinning. 

From  what  has  been  said,  it  seems  more  than  probable 
that  viscose,  as  well  as  viscoid,  may  in  the  future  strongly 
compete  with  celluloid,  the  cost  of  producing  it  being,  on 
the  one  hand,  less,  and  on  the  other,  it  is  not  nearly  as 
inflammable  as  celluloid,  the  great  combustibility  of  the 
latter  requiring  constant  precaution  in  handling  it. 

It  would  be  impossible  to  give  a  detailed  description  of 
all  the  uses  to  which  viscose  and  viscoid  might  be  applied. 
However,  the  suggestions  made  here  will  be  sufficient  to 
guide  the  practical  man  in  the  preparation  of  masses  with 
determined  properties. 

USE    OF    VISCOSE    IN    THE    MANUFACTURE    OF    PAPER. 

Since  by  the  decomposition  of  viscose  there  remains  be- 
hind a  substance  consisting  of  a  product,  which  has  to  be 
designated  as  paper  in  the  actual  sense  of  the  word,  no 
better  sizing-agent  for  paper  can  be  imagined.  In  view  of 
the  good  qualities  of  paper  sized  with  it,  the  use  of  viscose 
for  this  purpose  lias  been  widely  adopted  in  the  manufac- 
ture of  paper,  and  large  quantities  of  it  are  used. 

Although  soda-viscose  may  be  directly  used  for  sizing 
paper,  it  is  at  present  employed  only  in  exceptional  cases, 
the  removal  of  the  considerable  quantities  of  alkaline  salts 
which  pass  into  the  paper  mass  being  an  unpleasant 
operation. 

In  place  of  soda-viscose,  ammonium  viscose,  and  the  pre- 
viously-mentioned compounds  of  viscose  with  magnesium 
or  zinc,  are  at  present  used,  these  combinations  possessing 
the  advantage  of  decomposing  still  more  rapidly  than  soda- 
viscose.  In  addition  to  cellulose,  ammonium  viscose  and 


140  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

magnesium  viscose  in  decomposing  yield  throughout  com- 
binations soluble  in  water,  which  can  be  readily  removed 
by  washing  from  the  paper  mass.  Furthermore,  in  the 
decomposition  of  these  varieties  of  viscose,  a  far  less 
abundant  separation  of  carbon  disulphide  takes  place  than 
is  the  case  with  soda-viscose,  as  well  as  with  zinc-viscose. 
A  further  advantage  of  the  use  of  ammonium  or  magne- 
sium viscose,  as  well  as  of  zinc-viscose,  is  that  a  much 
smaller  quantity  of  alum  is  consumed  than  is  otherwise  the 
case. 

Papers  prepared  with  viscose  are  distinguished  by  a 
firmer  feel  and  besides,  by  the  addition  of  this  substance, 
great  strength  and  extensibility  are  imparted  to  them. 

Viscose  may  be  applied  to  all  kinds  of  paper,  to  the 
coarsest  qualities  of  wrapping  paper  as  well  as  the  finest 
varieties  of  writing  paper. 

As  shown  by  exact  experiments,  excellent  results  have 
been  obtained  by  the  application  of  viscose  as  a  size  to 
wrapping  paper  of  which  considerable  strength  is  demanded, 
the  breaking  length  as  well  as  the  elongation  being  in- 
creased 30  to  50  per  cent. 

Thorough  experiments  in  this  respect  have  been  made  by 
the  Versuchsanstalt  at  Charlottenburg,  and  the  figures 
given  below  show  plainly  how  the  qualities  of  the  papers 
are  affected  by  an  addition  of  viscose : 

Breaking  Elongation 

Variety  of  paper.  length  in  in         cent 

meters. 

Brown  wrapping  paper  from  steamed  wood 3575  1.80 

Same,  sized  with  4  per  cent,  of  viscose 4750  3.00 

Brown  wrapping  paper  from  steamed  wood 3200  0.90 

Same,  sized  with  4  per  cent,  of  viscose 4650  2.40 

Brown  wrapping  paper  from  steamed  wood 2225  1.40 

Same,  sized  with  4  per  cent,  of  viscose 2925  1.97 

If  fine  qualities  of  paper,  the  beautiful,  pure-white  color 
of  which  is  of  importance,  are  to  be  sized  with  viscose,  care 


VISCOSE    AND    VISCOID.  141 

must  be  taken  to  use  a  product  of  a  very  light  color,  other- 
wise the  paper  acquires  a  very  noticeable  yellowish  tinge. 

VISCOSE  IN  THE  MANUFACTURE  OF  WALL  PAPER. 

In  a  similar  manner  as  in  cloth  printing,  viscose  may  be 
directly  used  in  the  manufacture  of  wall  paper  as  a  thick- 
ening agent  for  the  printing  colors  employed  for  producing 
the  designs  upon  the  wall  paper.  As  compared  with  the 
ordinary  thickening  agents,  viscose  has  the  advantage  that 
the  colors  printed  with  it  adhere  far  more  firmly  to  the 
paper  than  is  the  case  with  other  colors  which  frequently 
stick  so  badly  as  to  be  effaced  by  slight  rubbing. 

The  use  of  viscose  is  of  special  advantage  in  the  manu- 
facture of  the  so-called  flock  paper,  which  is  made  by  sifting 
upon  sized  spots  of  the  wall  paper  finely  comminuted  colored 
wool  and,  after  drying,  removing  the  excess  of  wool  dust. 
From  most  of  the  flock  papers  the  larger  portion  of  the  wool 
can  be  readily  removed  by  vigorous  rubbing  with  a  brush, 
but  if  the  paper  be  printed  with  viscose  and  immediately 
covered  with  wool  dust,  the  latter  cannot  be  removed.  Me- 
tallic bronze,  aluminium  powder,  etc.,  triturated  with  vis- 
cose to  a  printing  color  and  printed  upon  the  paper,  look 
like  gilding  and  silvering  and  retain  for  years  their  metallic 
appearance. 

Even  wall  paper,  made  in  the  ordinary  way,  if  coated, 
when  finished,  with  viscose  solution  acquires  thereby  the 
beautiful  lustre  characteristic  to  pure  cellulose,  and  besides, 
it  may  be  cleansed  with  a  sponge  moistened  with  water, 
solution  of  soap  or  soda  without  damage  to  its  beautiful 
appearance.  Wall  paper  which  in  the  course  of  time  has 
suffered  from  smoke  and  dust  may  by  this  treatment  be 
restored  to  its  original  beauty.  Washing  may  be  repeated 
as  often  as  desired,  because  the  thin  layer  of  cellulose  upon 
the  paper  is  perfectly  water-proof  and  indifferent  towards 
water  and  soap. 

Imitations  of  leather  and  velvet  hangings  can   in   no 


142  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

other  way  be  made  so  beautiful  and  durable  as  with  the 
use  of  viscose.  By  printing  with  viscose  upon  leather- 
brown  paper,  gold  or  silver  bronze,  and  then  coating  its 
entire  surface  with  viscose,  it  can,  while  still  moist,  be  pro- 
vided with  raised  or  depressed  designs  so  that  in  appearance 
the  finished  wall-paper  cannot  be  distinguished  from  gen- 
uine leather  hangings. 

By  printing  designs  of  a  certain  form  upon  different 
places  of  the  paper  and  covering  them  with  wool  powder  of 
an  appropriate  color,  then  printing  other  places  with  vis- 
cose covering  them  also  with  different-colored  wool  powder, 
and  thus  continuing  the  operation,  wall  paper  may  be  pro- 
duced having  the  appearance  of  velvet  hangings  of  a 
determined  ground  color  with  variously-colored  flowers, 
leaves,  ornaments,  etc.,  woven  in.  It  is  advisable  to  pass 
wall  paper  made  in  this  manner  with  the  lower  non-printed 
surface  down,  over  a  heated  roll  with  such  rapidity  that 
the  viscose  layer  is  during  a  few  seconds  heated  to  212°  F. 
By  this  heating  the  viscose  becomes  perfectly  insoluble  and 
the  wall  paper  can  without  risk  be  rolled  up. 

The  examples  given  above  suffice  to  show  the  important 
role  viscose  is  likely  to  play  in  the  manufacture  of  wall 
paper. 

VISCOSE    IN    CLOTH-PRINTING. 

In  cloth-printing  viscose  may  be  used  in  various  ways, 
namely,  as  a  so-called  resist  and  as  a  thickening  and  fixing 
agent  for  certain  coloring  matters.  If  a  tissue  of  sheep's 
wool  or  silk  be  printed  with  various-colored  designs  by 
means  of  a  viscose  solution  of  appropriate  strength,  and  the 
tissue  be  then  passed  over  hot  rolls,  the  proper  places 
will  be  covered  and  impregnated  with  cellulose.  The 
tissue  may  then  be  dyed  in  a  dye-bath  which  yields  its 
coloring  matter  to  wool  and  silk,  but  not  to  cellulose,  the 
result  being  a  tissue  showing  a  white  design  upon  a  colored 
ground. 


VISCOSE    AND    VISCOID.  143 

If  the  printing  color  be  prepared  by  stirring  the  finely 
pulverized  coloring  matter  into  thick  viscose  solution  and 
the  tissue  be  printed  with  it,  it  is  only  necessary  for  fixing 
the  color  in  the  most  durable  manner,  to  pass  the  printed 
tissue  over  heated  rolls,  the  color  being  then  imbedded  in  a 
layer  of  cellulose  and  cannot  be  removed. 

Viscose  solution  can  to  great  advantage  be  used  for  mark- 
ing fabrics  in  mills,  as  well  as  a  substitute  for  ink  for  mark- 
ing household  linen,  etc.  For  this  purpose  a  viscose  solu- 
tion sufficiently  thickly-fluid  to  yield  sharp  impressions  with 
a  rubber  stamp  is  used,  a  durable  coloring  matter  being  in- 
corporated with  it,  finely-divided  carbon  in  the  form  of 
lamp-black  being  most  suitable  as  it  is  not  dissolved  by  any 
known  body.  The  tissues  are  marked  with  the  assistance 
of  the  rubber  stamp  and  after  drying  in  the  air,  the  color 
is  fixed  by  passing  a  hot  flat-iron  over  the  mark.  The  car- 
bon is  then  enclosed  by  cellulose,  and  the  color  is  not  only 
upon  the  surface  of  the  tissue  but  has  penetrated  it  through- 
out and  is,  therefore,  indestructible.  Even  an  attempt  to 
dissolve  the  layer  of  cellulose  enclosing  the  carbon,  by  treat- 
ment with  cuprammonium  solution,  would  result  only  in 
making  the  marking  somewhat  paler  and  less  distinct,  but 
it  would  be  impossible  to  destroy  it  entirely,  the  particles  of 
carbon  adhering  so  tenaciously  to  the  individual  fibres  of 
the  tissue  that  they  cannot  be  removed. 

In  place  of  carbon  any  desired  pulverulent  coloring  mat- 
ter may  be  used,  but  care  must  be  taken  that  it  is  of  such 
a  nature  as  not  to  be  changed  by  free  alkali  or  carbon  disul- 
phide. 

VISCOSE    AS    A    SIZE    OR    DRESSING. 

The  size  or  dressing  generally  used  in  the  textile  industry 
consists,  as  a  rule,  of  gum-like  substances,  a  paste  prepared 
from  various  kinds  of  starch  being  partially  employed  for 
the  purpose.  However,  these  agents  are  entirely  removed 
by  washing  the  fabrics  once  or  at  the  utmost  twice,  and  the 


144  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

latter  lose  their  good  appearance  and  firm  feel ;  as  well  as 
the  lustre  given  to  ihem  by  the  size  or  dressing. 

In  addition  the  weight  of  the  fabric  is  considerably  de- 
creased, because  the  pipe  clay  or  heavy  spar  which  had  been 
added  as  a  loading  agent  to  the  size,  has  also  been  washed 
out. 

Viscose  offers  a  means  of  sizing  tissues  in  such  a  manner 
that  they  retain,  even  after  repeated  washing,  their  smooth- 
ness and  lustre,  and  lose  nothing  in  body.  Sizing  with  vis- 
cose is  effected  in  various  ways  according  to  the  object  which 
is  to  be  attained. 

The  simplest  mode  of  sizing  consists  in  drawing  the  tissue 
from  a  drum  upon  which  it  has  been  wrapped  and  passing 
it  through  a  vat  filled  with  viscose  solution  of  suitable  con- 
centration. By  passing  the  wet  tissue  between  two  rubber 
rolls  set  close  together,  fixed  above  the  vat,  the  excess  01 
fluid  is  removed  and  falls  back  into  the  vat.  After  drying, 
the  tissue  appears  sized  with  a  layer  of  viscoid,  the  thick- 
ness of  which  depends. on  the  concentration  of  the  viscose 
solution  used.  By  passing  the  tissue  again  through  the 
viscose  solution  and  repeating  the  operation,  under  special 
conditions,  for  the  third  time,  sizing  is  finally  effected  to 
such  an  extent  that  all  the  pores  of  the  tissue  are  closed 
with  cellulose,  and  it  is  just  as  water-proof  as  if  it  had  been 
impregnated  with  rubber. 

Loading  agents  may  also  be  added  to  the  viscose,  thus 
imparting  great  weight  to  the  tissue,  which  it,  however,  re- 
tains when  washed,  because  the  particles  of  the  loading 
agent  are  cemented  one  to  the  other,  as  well  as  to  the  fibres 
of  the  tissue,  by  the  insoluble  cellulose. 

To  impart  to  the  tissue  treated  with  viscose  great  smooth- 
ness, and  at  the  same  time  a  beautiful  lustre,  it  is  advisable 
to  arrange  the  finishing  machine  so  that  the  tissue  after 
having  been  pressed  out  by  the  rubber  rolls,  passes  under 
high  pressure  through  two  polished,  hollow  rolls  heated 
by  steam.  By  this  heating,  the  viscose  is  instantly  con- 


VISCOSE    AND    VISCOID.  145 

verted  into  insoluble  cellulose  and  the  latter  is  forced  into 
the  separate  depressions  of  the  tissue,  thus  imparting  to 
the  latter  a  smooth  and  lustrous  surface. 

PREPARATION    OF    LEATHER-LIKE    BODIES    BY    MEANS    OF 

VISCOSE. 

The  results  of  all  the  attempts  to  produce  a  substance 
with  such  physical  properties,  especially  as  regards  tenacity 
and  strength,  that  it  would  answer  as  a  substitute  for  leather, 
have  to  be  accepted  only  conditionally,  and  all  products 
commended  under  the  names  of  artificial  leather  or  substi- 
tutes for  leather  have  to  be  viewed  with  a  certain  mistrust 
as  regards  their  durability  and  power  of  resistance.  The 
reason  for  the  failure  to  produce  a  substance  which  might 
satisfactorily  replace  leather,  is  found  in  the  nature  of  the 
latter  material  itself. 

Leather  is  the  portion  of  the  animal  skin  to  which  the 
term  corium  is  applied.  When  a  piece  of  corium  is  exam- 
ined under  the  microscope,  it  will  be  seen  to  consist  of  in- 
numerable fibres  twisted  together,  forming  an  extremely 
tough  substance.  By  the  tanning  process  the  fibres  of  the 
corium  are  coated  with  a  tanning  substance  which  prevents 
the  individual  fibres,  in  drying,  from  adhering  firmly  to- 
gether as  is  the  case  in  raw  hide,  the  latter  drying  to  a 
hard  horny  substance,  while  leather  remains  flexible. 

Hence,  if  a  substance  is  to  be  produced  which  shall  to  a 
certain  extent  possess  the  characteristic  strength,  tenacity 
and  durability  of  leather,  it  has  to  be  prepared  in  such  a 
manner  that  in  structure  it  approaches  that  of  leather. 
The  main  point  is,  therefore,  to  use  a  tissue  of  great 
strength  and  tenacity,  and  to  envelop  its  individual  fibres 
with  a  substance  possessing  also  great  strength  and  tenacity. 
With  reference  to  these  properties,  viscose,  or  viscoid  formed 
from  it,  plays,  as  will  be  directly  shown,  an  important  part, 
there  being  no  other  known  body  so  suitable  for  the  purpose. 

Hence,  in  order  to  produce  a  substance  which  as  regards 
10 


146  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

its  properties,  is  to  resemble  leather  as  closely  as  possible,  a 
tissue  of  suitable  quality  has  to  be  throughout  saturated 
with  viscose. 

Since  in  this  manner  masses  may  be  prepared  which  re- 
semble the  finest  qualities  of  glove  leather,  as  well  as  others 
which  come  up  to  sole  leather,  great  care  will  have  to  be 
bestowed  in  the  commencement  of  the  operation  upon  the 
fabric  to  be  manipulated.  For  very  thin  masses,  which,  as 
regards  their  properties,  are  to  resemble  glove  leather, 
closely-woven  cotton  fabrics  are  very  suitable,  and  as  the 
strength  of  every  kind  of  tissue  is  considerably  impaired  by 
bleaching,  it  is  advisable  to  use  only  unbleached  tissues 
except  in  case  the  material  to  be  prepared  is  to  be  of  a  pure 
white  color.  For  the  imitation  of  thicker  varieties  of 
leather,  such  as  uppers  for  shoes,  a  coarser  fabric  of  strong, 
unbleached  linen  may  be  employed,  as  well  as  a  tissue  of 
very  tough  Manila  hemp.  Finally,  for  the  imitation  of 
the  heaviest  varieties  of  leather,  thick  fabrics  of  very  tough 
fibres  are  used.  Such  fabrics  should  be  prepared  by  com- 
bining the  finest  fibres  by  doubling  to  coarser  fibres  which, 
when  interwoven,  yield  a  tissue  of  special  strength  and 
tenacity. 

In  working  up  these  various  fabrics  into  leather-like 
masses,  they  are  throughout  saturated  with  viscose  solution 
and  made  uniform  by  subsequent  mechanical  treatment, 
care  being  taken  to  keep  the  structure  of  the  fabric  entirely 
in  the  back  ground,  giving  the  material  as  far  as  possible 
the  appearance  of  leather. 

The  viscose  solutions  used  for  impregnating  the  tissues 
should  not  be  too  thinly-fluid,  a  solution  containing  about 
20  per  cent,  of  viscose  being  probably  most  suitable.  The 
use  of  a  more  highly  concentrated  solution  would  not  seem 
to  be  advisable,  because  it  is  then  so  thickly-fluid  as  to 
penetrate  only  with  great  difficulty  into  the  interior  of  the 
fabric.  Entirely  satisfactory  results  are  only  obtained  when 
the  tissue  has  been  saturated  throughout  its  entire  thick- 


VISCOSE    AND    VISCOID.  147 

ness,  so  that  on  examining  with  a  magnifying  glass  the 
cross  section  of  the  finished  product,  the  centre  presents  the 
same  appearance  as  the  portions  nearer  the  surface. 

The  first  step  in  the  operation  is  the  removal  of  all 
moisture  from  the  fabric  by  drying  it  thoroughly,  best  by 
means  of  hot  air.  It  is  then  placed  in  a  box,  closed  air- 
tight, in  which  it  remains  until  cooled  to  the  ordinary 
temperature,  and  ready  for  impregnation.  The  object  of 
this  drying  is  to  open  the  pores  of  the  fabric  so  tha,t  it  can 
be  readily  penetrated  by  the  viscose  solution. 

Imitations  of  leather  being,  as  a  rule,  colored,  dyeing  is 
effected  at  the  same  time  as  impregnation,  the  appropriate 
coloring  matter  being  added  to  the  viscose  solution,  the 
quantity  of  coloring  matter  required  for  the  various  kinds 
of  fabrics  being  determined  by  experiments.  Thick  fabrics 
require  less  coloring  matter  than  thin  ones,  because  by 
reason  of  the  fibres  in  the  body  of  the  tissue  being  also 
colored,  the  coloration  on  the  surface  appears  more  vivid 
than  is  the  case  with  thin  fabrics. 

The  vat  containing  the  viscose  solution  should  on  one 
side  be  provided  with  an  opening  for  the  entrance  of  the 
fabric  winding  off  a  roll.  The  fabric  is  carried  below  the 
level  of  the  fluid  by  three  rolls  revolving  with  ease.  Over 
the  second  of  these  rolls  is  fixed  a  pair  of  rolls  so  arranged 
that  the  distance  between  the  two  rolls  can  at  pleasure  be 
decreased  or  increased.  This  pair  of  rolls  is  set  to  corre- 
spond with  the  thickness  of  the  fabric  so  that  after  the 
latter  has  been  impregnated  with  viscose  solution,  it  is  only 
pressed  out  sufficiently  to  throw  off  the  excess  of  fluid 
adhering  to  it,  which  falls  back  into  the  vat. 

The  fabric  is  passed  through  the  viscose  solution  with 
sufficient  rapidity  to  allow  of  its  being  saturated  through- 
out its  entire  thickness.  The  rate  of  speed  must  be  slight 
for  thick  fabrics,  and  has  to  be  determined  by  direct  ex- 
periments. The  fabric  coming  from  the  impregnating  vat 
is  passed  through  rolls  heated  to  between  122°  and  140°  F., 


148  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

being  slightly  squeezed  thereby  without  being  actually 
pressed.  Heating  to  the  above-mentioned  temperature  is 
best  effected  by  hollow  rolls  heated  by  steam  constantly 
passing  through  them.  During  the  passage  of  the  fabric 
between  these  heated  rolls,  the  conversion  of  viscose  into 
viscoid  takes  place,  one  hot  pair  of  rolls  being,  as  a  rule, 
sufficient  for  thin  fabrics,  while  for  thick  fabrics  a  second 
or  third  pair  of  rolls  will  have  to  be  used. 

In  place  of  using  heated  rolls,  the  fabric  may  be  simply 
passed  over  loosely-lying  rolls  while  a  current  of  hot  air  as- 
cends from  beneath,  the  viscose  being,  in  this  case,  also  de- 
composed. 

As  has  been  previously  explained,  by  the  decomposition 
of  the  viscose,  vapors  of  carbon  disulphide  and  other  gases 
are  constantly  disengaged.  To  protect  the  workmen  from 
these  injurious  vapors,  the  rolls  through  and  over  which  the 
fabrics  pass,  should  be  placed  in  a  closed  box,  and  the  latter 
be  connected  with  a  ventilator,  which  constantly  sucks  air 
into  the  box  and  carries  it  off.  It  is  advisable  to  connect 
the  ventilator  to  a  fire-box  in  which  the  carbon  disulphide 
vapors  are  burned  to  sulphurous  and  carbonic  acids. 

When  working  6n  a  large  scale,  it  will  certainly  pay  to 
recover  and  condense  the  carbon  disulphide  vapors.  For 
this  purpose  provision  has  to  be  made  for  a  long  coil  placed 
in  a  vessel  filled  with  cold  water,  in  which  the  warm  air 
and  the  vapors  carried  along  with  it  are  first  cooled  to  the 
ordinary  temperature.  From  this  preparatory  cooler,  the 
vapors  are  driven  into  a  vessel  filled  with  ice,  in  which  the 
carbon  disulphide,  vapor  is  condensed  and  runs  off  with  the 
ice  water. 

The  fabrics  having  been  carried  through  the  heated  rolls 
or  over  a  current  of  hot  air,  are  next  exposed  to  strong 
pressure  by  being  passed  between  smooth  rolls,  in  order  to 
give  them  an  entirely  smooth  surface.  They  are  then  re- 
peatedly washed  in  water  to  free  them  from  alkali,  and  are 
finally  dried  in  the  air  or  in  artifically-heated  rooms. 


VISCOSE    AND    VISCOID.  149 

In  working  thick  fabrics,  one  impregnation  with  viscose 
solution  is  frequently  found  insufficient  to  saturate  them 
throughout  their  entire  thickness.  Such  fabrics  having  been 
passed  through  the  heated  rolls  and  cooled  to  the  ordinary 
temperature,  are  subjected  to  another  treatment  with  viscose 
solution,  the  operation  being  exactly  the  same  as  previously 
described. 

The  fabrics  impregnated  according  to  the  process  given 
above  are  now  in  the  following  condition  :  All  the  fibres  of 
the  fabric  are  enveloped  by  cellulose  and  the  empty  spaces 
between  the  separate  threads  and  fibres  are  also  filled  with 
it,  so  that  the  whole  represents  quite  a  uniform  mass  of  cel- 
lulose. However,  the  portion  of  the  mass  belonging  to  the 
fabric  is,  in  consequence  of  its  structure,  exceedingly  tough 
and  strong,  it  having  acquired  these  properties  in  a  still 
higher  degree  by  being  enveloped  and  cemented  by  the 
cellulose.  It  will  be  seen  that  such  a  fabric,  as  regards  its 
structure,  may  be  compared  with  leather,  the  fibres  repre- 
senting the  skin  tissue,  while  the  cellulose  which  envelops 
them  serves  for  their  consolidation  and  reinforcement. 

The  impregnated  fabrics,  when  washed  and  again  made 
air-dry,  possess  quite  a  high  degree  of 'elasticity  and  a  cer- 
tain softness,  and  can  without  difficulty  be  further  worked 
by  mechanical  means.  By  passing  them  through  brightly 
polished  rolls  capable  of  producing  great  pressure,  they  ac- 
quire a  very  smooth  surface  and  high  lustre.  After  going 
through  these  rolls  they  may  be  passed  through  others  en- 
graved in  various  ways,  for  instance,  for  the  imitation  of 
morocco  leather.  When  coloring  has  been  properly  done, 
such  imitation  can  scarcely  be  distinguished  from  the  gen- 
uine product. 

However,  success  in  giving  a  fine  appearance  to  an 
article  to  be  used,  is  of  only  secondary  importance,  since  by 
coloring  and  pressing  paper  it  may  be  given  a  striking  re- 
semblance to  morocco  leather.  But  imitations  of  leather 
made  according  to  the  process  given  above,  have  in  addition 


150  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

to  appearance  another  valuable  property,  namely,  strength 
and  tenacity  of  substance.  A  piece  of  leather  may  be  torn 
with  greater  ease  than  a  piece  of  fabric  of  the  same  thick- 
ness impregnated  with  cellulose. 

Thick  fabrics  impregnated  with  cellulose  may  be  used  for 
shoe  soles,  since  they  have  the  advantage  over  leather  soles 
of  not  becoming  soft  when  exposed  for  a  long  time  to  damp- 
ness and  shriveling  to  a  hard  mass  as  is  the  case  with 
leather  which  by  the  action  of  moisture  is  deprived  of  a 
large  portion  of  its  content' of  tannin.  Impregnated  fabrics 
being  entirely  indifferent  towards  water  are  only  gradually 
destroyed  by  the  mechanical  wear  and  tear  in  using  the 
shoes. 

Leather  belts  for  machines  are,  as  is  well  known,  quite 
expensive,  as  they  have  to  be  made  of  the  heaviest  and  most 
carefully  tanned  qualities  of  leather.  They  may,  however, 
be  advantageously  replaced  by  belts  made  of  very  strong 
fabrics  impregnated  with  cellulose.  Such  belts  up  to  0.39 
to  0.59  inch  thick  are  produced  by  impregnating  thinner 
fabrics  and  cementing  them  together  with  viscose  solution. 

In  the  above  explanations,  the  principal  elements  have 
been  given  which  must  be  adhered  to  in  the  preparation  of 
imitations  of  leather  in  order  to  obtain  satisfactory  results, 
and  by  observing  them,  it  will  not  be  difficult  for  a  manu- 
facturer who  takes  up  the  subject,  to  prepare  various  pro- 
ducts which  possess  the  character  of  the  leather  to  be 
imitated,  and  are  distinguished  by  considerable  strength. 

However,  not  only  tissues  can  be  converted  into  leather- 
like  masses,  but  also  fabrics  of  a  felt-like  nature,  such  as 
felt  itself,  further  felted  cotton,  and  pasteboard. 

When  ordinary  pasteboard  prepared  from  mechanical 
wood-pulp  be  throughout  saturated  with  viscose  solution 
and  then,  under  constantly  increasing  pressure,  passed  be- 
tween smooth  rolls,  a  mass  is  obtained  which  in  hardness 
considerably  surpasses  the  best  quality  of  pressing-board, 
and,  as  regards  tenacity  and  elasticity,  can  only  be  com- 


VISCOSE    AND    VISCOID.  J51 

pared  with  very  hard  wood.  It  can  be  worked  with  all 
kinds  of  wood-working  tools.  On  the  other  hand,  it  can, 
while  still  wet,  be  pressed  into  any  desired  form  by  suitable 
dies,  and  thus  plates  may  be  produced  which  equal  in  ap- 
pearance carved  wood,  and  may  to  advantage  be  utilized  in 
the  manufacture  of  furniture.  By  the  use  of  engraved 
plates  which  may  also  be  provided  with  high  reliefs,  book 
covers  of  elegant  appearance  may  be  produced  from  paste- 
hoard  thus  prepared,  these  book  covers  having,  independent 
of  their  cheapness,  the  advantage  of  being  almost  inde- 
structible. 

Since  paste-board  plates  only  0.19  inch  thick,  possess, 
when  impregnated  with  cellulose,  a  strength  and  power  of 
resistance  equal  to  that  of  quite  thick  boards,  they  would 
seem  to  be  an  excellent  material  for  the  construction  of 
portable  houses,  such  as  are  required  for  scientific  expedi- 
tions, for  the  erection  of  observatories  upon  high  mountains, 
etc. 

Such  plates  can  be  rendered  fire-proof  by  treating  them, 
while  still  moist,  with  alum  solution,  and  then  with  water- 
glass  solution,  so  that  a  house  constructed  from  this  light 
material  can  scarcely  burn  down. 

Genuine  felt  consists  of  tangled  animal  hair  combined  by 
fulling  and  beating  to  a  quite  solid,  and  at  the  same  time 
porous,  mass.  By  reason  of  its  porous  nature  it  can  be 
readily  impregnated  with  fluids.  Felt  plates  impregnated 
with  viscose  solution  completely  retain  their  flexibility  and 
suppleness,  and  being  waterproof,  may  be  used  for  hats, 
clothing,  tents,  etc.  If,  previous  to  their  being  treated  with 
viscose  solution,  they  are  soaked  in  a  saturated  solution  of 
borax  in  water,  and  then  thoroughly  dried,  they  become 
absolutely  indestructible,  the  rotting  of  the  felt  by  repeated 
exposure  to  moisture  being  prevented  by  the  highly  anti- 
septic properties  characteristic  of  boric  acid.  Hence  felt- 
plates  prepared  in  this  manner  can  be  laid  directly  in  the 
ground  as  a  support  for  heavy  machinery,  and  thus  the 


152  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

noise  of  the  latter,  when  resting  upon  an  unyielding  founda- 
tion, can  he  almost  entirely  obviated. 

VISCOSE  IN  THE  MANUFACTURE  OF  ARTIFICIAL  FLOWERS. 

For  the  manufacture  of  imitations  of  flowers,  leaves,  etc., 
variously-colored  stuffs,  as  well  as  paper,  are  used,  the  sub- 
stances being  appropriately  shaped,  then  painted,  and,  if 
required,  varnished.  Although,  as  regards  artistic  execu- 
tion, such  artificial  flowers  are  beautiful,  they  delineate 
only  in  a  very  incomplete  manner  the  appearance  of  natural 
flowers  and  leaves. 

Great  progress  was  made  by  the  introduction  of  celluloid 
in  the  manufacture  of  artificial  flowers  as  this  material  can 
be  readily  colored  any  shade,  and  moulded  into  any  desired 
form.  The  high  lustre  peculiar  to  articles  of  celluloid  had, 
in  this  case,  the  effect  of  still  further  increasing  the  beauti- 
ful appearance  of  such  artificial  flowers.  But  they  are  un- 
fortunately quite  expensive,  and  possess  the  further  disad- 
vantage of  being  extremely  inflammable. 

However,  in  viscose  the  manufacturer  has  at  his  disposal 
a  material  which  deserves  consideration,  it  being  not  only 
very  cheap,  no  more  inflammable  than  ordinary  paper,  and 
possesses  other  advantages  which  make  it  very  suitable  for 
the  object  in  question.  The  mode  of  application  in  the 
manufacture  of  artificial  flowers  would  probably  be  to  satur- 
ate thin,  porous  tissue-paper  with  appropriately-colored  vis- 
cose, and  to  cut  out  the  flowers,  leaves,  etc.,  by  means  of 
heated  dies.  By  contact  with  the  heated  die,  the  viscose  is 
rapidly  changed  to  viscoid,  and  the  leaves,  etc.,  retain  ex- 
actly the  shape  given  to  them  by  the  dies.  The  leaves  are 
smooth  and  lustrous  and,  of  course,  have  all  the  properties 
belonging  to  viscoid.  They  may  be  immersed  in  water 
without  losing  their  shape  or  suffering  any  other  injury, 
and  when  they  have  become  unsightly  by  dust,  they  may 
even  be  cleansed  by  means  of  an  atomizer  and  water. 

For  especially  delicate  artificial  flowers,  pure  viscose  may 


VISCOSE    AND    VISCOID.  153 

be  used  by  allowing  a  thick  viscose  solution  to  dry  upon 
glass  plates  to  thin  plates  and  making  the  leaves,  etc.,  from 
the  latter.  By  adding  sufficient  quantities  of  coloring 
matter  to  the  viscose  solution,  colored,  transparent  leaves  of 
viscoid  are  obtained  which,  when  worked  into  flowers,  pro- 
duce a  peculiar  effect  resembling  that  seen  in  glass  flowers. 

VISCOSE    IN    PHOTOGRAPHY. 

Some  kinds  of  photographic  apparatus  are  so  arranged 
that  the  picture  is  taken  upon  a  transparent  film,  instead 
of  upon  a  glass  plate.  Such  a  film  can  be  produced  of  any 
length  and  wound  upon  a  roll,  and  the  use  of  such  a  pho- 
tographic apparatus  is  very  convenient,  especially  in  expe- 
ditions, as  it  requires  but  little  space,  and  a  large  number 
of  pictures  can  be  readily  taken. 

At  present  the  films  are  almost  exclusively  made  of 
celluloid  membranes,  which,  however,  are  not  so  well 
adapted  for  the  purpose  as  viscose,  the  latter  being  less  in- 
flammable, and  less  sensitive  to  moisture  and  heat  than 
celluloid. 

The  preparation  of  films  from  viscose  is  a  very  simple 
matter.  The  length  of  a  film  being  generally  such  that 
twelve  pictures  can  be  taken  with  one  roll  of  it,  a  piece  of 
plate  glass  corresponding  in  length  to  that  of  the  roll  of 
film  has  to  be  procured,  allowing  in  addition  a  few  centi- 
meters for  the  portion  of  the  film  secured  to  the  roll.  The 
film  being,  as  a  rule,  larger  in  width  than  in  thickness,  the 
plate  glass  should  be  wide  enough  to  allow  of  a  large  film- 
plate  being  at  one  time  made,  which  is  then  cut  up. 

The  plate-glass  is  surrounded  by  a  metal  frame  project- 
ing a  few  millimeters  above  it,  its  object  being  to  prevent 
the  viscose  solution  from  running  off  the  plate-glass.  The 
latter  is  placed  upon  a  stand  provided  with  a  ball-joint 
capable  of  being  turned  by  friction,  so  that  the  plate-glass 
can  be  readily  set  in  a  level  position. 

The  viscose  solution  used  for  the  preparation  of  films 


154  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

should  be  of  such  concentration  that,  when  poured  in  a 
layer  of  a  fixed  depth  upon  the  plate-glass,  it  yields,  after 
drying,  a  membrane  of  sufficient  thickness ;  this  can  be 
readily  ascertained  by  a  few  experiments.  The  viscose 
solution  is  poured  upon  the  plate  glass  by  commencing  in 
one  corner  of  the  latter,  care  being  taken  that  no  bubbles 
are  formed,  and  as  the  fluid  spreads  out  over  the  plate-glass, 
pouring  is  continued  until  the  entire  surface  of  the  plate- 
glass  is  uniformly  covered. 

The  plate-glass  is  then  left  standing  without  being 
touched  until  the  viscose  layer  is  entirely  congealed.  It  is 
then  taken  off  and  heated  upon  a  plate  of  aluminium  sheet 
to  212°  F.,  until  it  has  become  insoluble.  It  is  then 
washed  with  water  and  completely  dried  in  the  air.  The 
large  plate  of  viscoid,  which  should  have  the  appearance  of 
colorless  glass,  is  then  cut  up  into  strips  of  film  of  suitable 
length,  and  the  latter  are  treated  with  chemicals  to  form  a 
layer  sensitive  to  light  upon  their  surfaces. 

VISCOID    MASSES. 

If  a  viscose  solution  be  allowed  to  stand  quietly  at  the 
ordinary,  or  a  somewhat  higher,  temperature,  it  decomposes 
slowly,  and  a  plate  remains  behind,  the  thickness  of  which 
depends  on  the  depth  of  the  original  viscose  solution.  In 
order  to  obtain  homogeneous  viscose  masses  free  from 
bubbles,  the  decomposition  of  the  mass  should  not  be  has- 
tened by  heating,  as  otherwise  the  vapors  and  gases  escap- 
ing from  the  mass  after  it  has  already  become  thickly-fluid, 
would  cause  the  formation  of  bubbles  in  it,  such  as  may  be 
observed  in  ordinary  glass.  If,  on  the  other  hand,  the 
mass  is  allowed  to  stand  at  the  ordinary  temperature  until 
it  has  acquired  the  consistence  of  solid  jelly,  it  may  be  care- 
fully lifted  from  the  vessel  containing  it  and  placed  upon  a 
glass  plate,  the  latter  being  allowed  to  lie  in  a  place  free 
from  dust  until  the  mass  is  entirely  solid.  It  is  then  slowly 
heated  to  212°  F.,  so  that  it  becomes  heated  throughout, 


VISCOSE    .AND    VISCOID.  155 

and  then  placed  in  water  for  the  purpose  of  dissolving  the 
salts  present.  By  exposing  such  a  block  to  a  strong  pres- 
sure, allowing  it  to  stand  under  it  for  some  time,  a  body  is 
obtained  which,  in  appearance,  does  not  much  differ  from 
a  block  of  glass. 

This  pure  viscoid  may  be  worked  with  all  kinds  of  tools. 
It  can  be  sawed,  drilled  and  worked  in  the  lathe,  and  forms 
an  excellent  material  for  the  manufacture  of  various  fancy 
articles.  If  a  coloring  matter  insoluble  in  water  has  been 
added  to  the  viscose  solution,  the  viscoid  also  appears 
colored. 

Since  by  mixing  viscose  with  various  indifferent  bodies, 
masses  may  be  prepared  which  present  a  pleasing  appear- 
ance, and  are  much  cheaper  than  pure  viscoid  by  itself, 
they  may  be  advantageously  used  for  the  production  of 
numerous  small  fancy  articles.  When  properly  made  they 
present  almost  exactly  the  rame  appearance  as  celluloid 
articles,  but  are  much  cheaper  and  not  so  inflammable. 

Viscose  possessing  great  viscosity,  considerable  quantities 
of  foreign  bodies  can  be  incorporated  with  it  and  the  result- 
ing viscoid  masses  be  nevertheless  very  strong,  and  of  beau- 
tiful appearance.  There  are  a  large  number  of  substances 
which  may  be  used  for  filling  viscoid  masses,  and  in  fact 
every  kind  of  pulverulent  body  which  is  chemically  indif- 
ferent to  viscose  may  thus  be  employed.  For  the  preparation 
of  white  masses  there  are,  for  instance,  available,  pulverized 
chalk,  plaster  of  Paris,  magnesium  carbonate,  zinc  white, 
powdered  talc  (soapstone  powder)  and  pulverized  heavy 
spar,  or  preferably  artificially-prepared  heavy  spar,  the  so- 
called  permanent  white,  which  is  an  extremely  delicate 
powder.  According  to  the  substance  used,  there  will  be 
considerable  difference  in  the  resulting  masses  as  regards 
weight,  and  partially  also  as  regards  lustre.  Masses  of  a 
pure  milk-white  color  and  of  comparatively  slight  specific 
gravity  can  be  produced  with  the  use  of  magnesium  car- 
bonate, tlie  latter  being  a  pure  white  powder  of  very  slight 


156  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

specific  gravity.  Masses  prepared  with  pulverized  chalk  or 
plaster  of  Paris,  though  light,  are  heavier  than  magnesium 
masses. 

The  lightest  viscoid  masses  of  a  white  color  are  prepared 
by  mixing  with  the  viscose  as  a  filling-substance  bleached 
cellulose  made  from  wood  by  the  sulphite  or  soda  process. 
A  product  of  not  quite  such  a  pure  white  color,  but  never- 
theless of  nice  appearance,  is  obtained  with  the  use  of 
mechanical  wood-pulp  prepared  from  a  white  wood,  for 
instance,  aspen ;  such  masses  have  a  very  slight  yellowish 
tint. 

Since  viscose  solution  may  be  colored  as  desired,  the 
white  basis-masses  given  above  may  be  used  for  the  pre- 
paration of  colored  viscoid  masses,  though  the  latter  may 
also  be  obtained  by  mixing  with  the  white  pulverulent 
filling  substances  other  colored  powders. 

Viscose  solutions,  even  if  quite  dilute,  possess  a  consider- 
able degree  of  viscosity,  and  the  preparation  of  homogeneous 
masses  with  the  use  of  filling-substances  presents  certain 
difficulties,  uniform  mixing  of  the  solution  with  the  pow- 
ders being  only  accomplished  by  long-continued  manipula- 
tion. Besides,  the  various  powders  act  differently  in  this 
respect  towards  viscose,  and  it  is  advisable  first  to  make 
experiments  on  a  small  scale.  For  this  purpose  a  fixed 
quantity  of  dilute  (at  the  utmost  10  per  cent.)  viscose  solu- 
tion and  a  fixed  quantity  of  the  powder  to  be  used  for 
filling  are  employed,  for  instance,  1  quart  of  viscose  and  22 
Ibs.  of  powder.  Pour  the  viscose  into  a  large,  round  vessel, 
smooth  inside,  for  instance,  a  porcelain  dish,  and  while  one 
workman  constantly  stirs  the  viscose,  another  one  pours  the 
powder  in  a  fine  jet  into  the  fluid  until  a  thick  paste  is 
'  formed,  which  cannot  be  further  worked  with  the  stirrer. 

This  paste  is  rolled  out  on  a  smooth  plate — a  marble  slab 
being  very  suitable  for  the  purpose — and  the  plate  thus 
obtained  is  folded  over  and  again  rolled  out,  the  operation 
being  repeated  until  a  uniform  mass  is  obtained  which  is 


VISCOSE    AND    VISCOID.  157 

still  sufficiently  plastic  that,  when  subjected  to  quite  a 
strong  pressure  in  a  mould,  all  the  elevations  and  depres- 
sions are  reproduced.  The  moulded  articles  are  allowed  to 
stand  quietly  until  perfectly  dry.  The  quality  of  these 
test-pieces  furnishes  accurate  information  regarding  the 
properties  of  the  mass. 

A  viscoid  mass  of  the  proper  quality  should  possess  beau- 
tiful lustre,  and  be  so  hard  and  solid  that  it  can  only  be 
broken  with  difficulty  by  vigorous  blows  with  a  hammer. 
When  the  mass  breaks  under  the  hammer  into  several 
pieces,  and  consequently  is  brittle,  it  is  indicative  of  too 
large  a  quantity  of  filling-substance  having  been  used.  In 
this  case  the  fractures  are  very  uneven,  dull  and  lustreless, 
while,  on  the  other  hand,  the  fracture  of  a  mass  containing 
not  too  large  a  quantity  of  filling-substance  should  be  con- 
choidal,  with  sharp,  smooth  edges,  and  lustrous. 

When  the  quality  of  the  test-mass  is  found  to  come  up 
to  the  standard,  the  composition  of  the  mass  for  the  prepa- 
ration of  larger  quantities  of  it  can  be  calculated  from  the 
amount  of  filling-substance  and  viscose  solution  used. 

For  the  preparation  of  larger  quantities  of  viscoid  masses 
special  mechanical  contrivances  have  to  be  employed  which 
allow  of  the  thorough  kneading  together  of  the  fluid  and 
the  powder.  Mixing  or  kneading  machines,  such,  for  in- 
stance, as  imitate  kneading  bread-dough  by  hand,  are  best 
adapted  for  the  purpose,  since  with  such  machines  any 
desired  power  may  be  applied.  Mixing  and  kneading  ma- 
chines of  this  kind  performing  excellent  work  are,  for  in- 
stance, constructed  by  Werner  and  Pfleiderer,  the  work  of 
^borough  mixing  being  effected  by  an  implement  of  peculiar 
construction,  the  so-called  mixing  paddle.  A  large  number 
of  machines  of  this  kind  are  at  present  in  use  in  bread 
bakeries,  paint  factories — in  fact  in  all  kinds  of  establish- 
ments where  masses  have  to  be  mixed  and  kneaded — and 
are  most  suitable  for  the  preparation  of  viscoid  masses. 
However,  to  adapt  them  entirely  for  this  purpose,  the  mix- 


158  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

ing  vessel  must  be  so  arranged  that  it  can  be  tightly  closed, 
so  that  the  viscose  does  not  decompose  during  the  operation, 
since  decomposition  should  only  be  effected  when  the  plastic 
mass  is  brought  into  the  form  the  finished  article  is  to  have. 
Fig.  32  shows  the  peculiar  shape  of  a  kneading  and  mixing 
paddle  of  a  kneading  and  mixing  machine  constructed  by 
Werner  and  Pfleiderer. 

In  the  commencement  of  the  operation,  the  entire  quan- 
tity of  viscose  solution  to  be  worked  is  brought  into  the 

FIG.  32. 


mixing  vessel,  and  through  a  funnel  placed  in  the  lid  of 
the  mixing  vessel  the  powder  is  allowed  to  run  in  in  a  thin 
jet,  while  the  mixing  paddle  revolves  with  moderate  ve- 
locity. When,  in  consequence  of  the  increasing  viscosity 
of  the  mass,  its  resistance  to  the  mixing  paddle  becomes 
greater,  the  velocity  of  the  latter  is  increased,  and  thus 
continued  until  a  sample  taken  from  the  mixing  vessel 
shows  the  mass  to  be  entirely  uniform.  The  machine  is 
then  stopped,  the  viscoid  mass  taken  out  and  immediately 
moulded. 


'X  A' 


VISCOSE    AND    VISCOID.  159 

The  moulds  used  may  be  made  of  iron  of  brass,  or  of 
wood,  gutta-percha,  or  of  plaster  of  Paris  impregnated  with 
stearin.  Moulds  which  are  most  frequently  used  should,  of 
course,  be  made  of  metal,  this  material  possessing  the  great- 
est power  of  resistance  and  being  less  subject  to  wear  and 
tear. 

It  depends  on  the  article  to  be  prepared  whether  it  is  to 
be  moulded  solid  or  hollow.  Billiard  balls,  door-handles, 
buttons,  ornaments  in  relief,  etc.,  are  moulded  solid.  For 
the  preparation  of  balls,  hemispherical  moulds  are  used. 
They  are  pressed  full  of  viscoid  mass  and,  after  coating  two 
such  hemispheres  with  a  small  quantity  of  thick  viscose 
solution,  they  are  joined  together  by  vigorous  pressure.  In 
this  manner  cane-heads,  door-knobs,  etc.,  are  made. 

For  moulding  hollow  articles,  plates  of  the  thickness  the 
articles  are  to  have  are  first  prepared  from  the  mass.  Such 
a  plate  is  pressed  into  the  hollow  mould,  the  core  portion 
of  the  mould  is  then  laid  upon  it,  and  the  mould  thus  put 
together  is  subjected  to  pressure  in  a  press,  by  which  any 
excess  of  mass  is  forced  from  the  mould.  When  the  press 
is  opened  the  core  portion  of  the  mould  is  first  lifted  off, 
and  the  article  can  then  be  readily  detached  by  turning  the 
mould  over  and  giving  it  a  gentle  knock.  Doll-heads  are 
thus  made  in  two  halves,  which  are  then  cemented  together 
with  viscose  solution. 

The  articles  when  taken  from  the  moulds  being  still  soft 
have  to  be  carefully  laid  upon  a  smooth  board  and  allowed 
to  remain  in  a  place  free  from  dust  until  they  are  solid, 
hard  and  dry.  They  are  then  finished  by  heating  to  about 
212°  F.  In  case  the  articles  should  turn  out  lustreless,  a 
beautiful  lustre  can  be  given  to  them  by  applying  a  coat  of 
dilute  (10  per  cent.)  viscose  solution.  When  the  articles 
are  to  be  painted,  for  instance,  doll-heads,  the  colors  are 
applied  to  the  finished  article,  a  coating  of  viscose  solution 
being  finally  put  on.  The  colors  then  lie  under  a  thin 
colorless  layer  of  cellulose  similar  to  a  coat  of  a  protecting 


160  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

glaze,  and  the  articles  may  be  cleansed  with  soap  and  water 
without  injury  to  the  colors. 

Viscoid  masses,  the  filling-substances  of  which  consist  of 
•cellulose  or  mechanical  wood-pulp,  acquire  a  hardness  not 
surpassed  by  hard  wood,  and  may  be  advantageously  used 
for  machine  parts  which  otherwise  have  to  be  made  by 
hand  from  wood.  Screws  and  nuts  may  thus,  for  instance, 
be  made  from  the  mass  while  still  soft,  and  they  do  not 
require  finishing  by  hand,  because  coming  from  the  same 
mould  they  have  the  same  gauge.  In  the  same  manner 
.shuttles,  spools,  small  cog-wheels,  etc.,  may  be  prepared  by 
pressing,  the  cost  of  producing  such  articles  being,  as  may 
readily  be  conceived,  very  slight  as  compared  with  those 
made  by  hand  from  wood. 

Viscoid  masses  filled  either  with  cellulose,  mechanical 
wood-pulp,  or  indifferent  mineral  powders  possess  in  a  high 
degree  the  power  of  resisting  atmospheric  influences,  and 
suffer  neither  from  rain  or  frost.  In  consequence  of  these 
valuable  properties  they  are  well  adapted  for  building  pur- 
poses, for  the  exterior  as  well  as  the  interior  of  houses. 
Mouldings,  cornices,  lion  heads  and  other  constructive  orna- 
ments may  be  advantageously  made  of  this  mass,  which  is 
cheap,  and  at  the  same  time  capable  of  great  resistance, 
and  it  may  also  be  used  for  busts,  statuettes  and  ceramic 
articles. 


VIII. 

NITRO-CELLULOSE  (GUN-COTTON,  PYROXYLIN). 

WHEN  pure  cellulose  is  brought  in  contact  with  more  or 
less  concentrated  nitric  acid,  a  large  number  of  combina- 
tions is  formed,  the  kind  of  combinations  which  are  formed 
depending  on  the  concentration  of  the  acid,  as  well  as  on 
the  time  it  remains  in  contact  with  the  cellulose.  How- 
ever, there  are  two  distinctly  marked  groups  of  combina- 
tions, one  of  them  being  distinguished  by  its  members 
exploding  with  great  violence  when  brought  in  contact 
with  a  red-hot  body,  as  well  as  by  concussion  and  percus- 
sion, and  further  by  being  indifferent  towards  solvents. 
The  second  group,  to  be  sure,  also  contains  explosive  bodies, 
they  being,  however,  distinguished  by  the  property  of  com- 
pletely dissolving  in  certain  fluids.  Hence  we  may  speak 
of  explosive  nitro-celluloses  and  soluble  ones,  but  it  must 
be  expressly  understood  that  an  absolutely  sharp  boundary 
between  these  two  groups  is  not  known. 

The  combinations  formed  by  the  action  of  nitric  acid 
upon  cellulose  were  simultaneously  discovered  by  Braconnet, 
Schonbein,  Otto  and  Pelouze,  the  explosive  products  for 
blasting  and  military  purposes  being  first  prepared  by 
them.  The  properties  of  the  less  explosive,  but  readily 
soluble,  combinations,  as  well  as  the  numerous  uses  to 
which  they  could  be  applied,  became  accurately  known 
only  at  a  much  later  time.  They  are  at  present  so  num- 
erous that  several  large  industries — manufacture  of  arti- 
ficial silk  and  of  celluloid — are  based  upon  them. 

According  to  former  opinions  regarding  the  formation 
and  composition  of  the  combinations  belonging  to  these 
11  (16J) 


162  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

groups,  they  were  considered  as  nitro-compounds.  In 
accordance  with  this  assumption,  by  treating  cellulose  with 
nitric  acid,  the  water  is  withdrawn  from  the  cellulose  and 
replaced  by  nitryl,  the  radical  of  nitric  acid.  However, 
when  it  was  found  that  by  treating  cellulose  for  a  longer  or 
shorter  time,  as  well  as  at  different  temperatures,  with  vary- 
ing quantities  of  nitric  acid,  combinations  containing  differ- 
ent quantities  of  nitrogen  were  formed,  it  was  sought  to 
explain  this  phenomenon  by  the  existence  of  different 
kinds  of  nitre-cellulose,  and  thus  hypothetical  compounds 
which  were  to  contain  1  to  11  molecules  of  nitryl  were 
arrived  at.  It  was  further  considered  justifiable  to  assume 
that  nitro-celluloses  with  a  certain  content  of  nitrogen  are 
insoluble,  while  others  constitute  the  soluble  form.  How- 
ever, since  nitro-celluloses  can  be  prepared  which  possess 
nearly  the  same  content  of  nitrogen,  but  one  of  which  is  in- 
soluble and  the  other  readily  soluble,  these  opinions  can  no 
longer  be  considered  correct. 

According  to  modern  views  regarding  the  composition  of 
gun-cotton,  it  cannot  be  designated  a  nitro-compound,  but 
has  to  be  termed  a  nitric  acid  ester  or  ether,  the  proof  of 
the  correctness  of  this  view  being  found  in  the  behavior  of 
gun-cotton  towards  different  reagents.  In  treating  gun- 
cotton  with  concentrated  sulphuric  acid  it  is  slowly  decom- 
posed, even  at  the  ordinary  temperature,  and  nitric  acid  is 
liberated.  If  gun-cotton  be  treated  with  potash-lye  it  is, 
even  if  only  slightly  heated,  completely  decomposed,  potas- 
sium nitrate  being  formed,  and  the  cellulose  with  all  its 
properties  reappears.  Even  ferrous  chloride  acts  upon 
nitro-cellulose  in  such  a  way,  that  the  formation  of  ferric 
chloride  is  caused  by  the  nitric  acid  which  is  liberated,  and 
cellulose  is  again  formed. 

In  view  of  these  reactions  the  assumption  that  the  so- 
called  nitro-cellulose  is  a  combination  formed  by  the  re- 
placement of  the  hydrogen  in  the  cellulose  by  the  radical 
nitryl  can  no  longer  be  maintained,  and  the  view  that  a 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  163 

series  of  combinations  of  cellulose  with  nitric  acid — cellulose 
nitric  acid  esters — is  in  question,  would  seem  to  be  correct. 
From  this  also  results  the  assumption  of  a  mono- cellulose, 
di-cellulose,  tri-cellulose,  up  to  endeca-cellulose,  and  the 
quantity  of  nitrogen  found  in  the  products  depends  on  the 
concentration  of  the  nitric  acid  used,  as  well  as  on  the 
duration  of  the  action  of  the  acid  upon  the  cellulose. 

Nitro-cellulose,  in  explosive  as  well  as  soluble  form,  may 
be  prepared  by  bringing  pure  cellulose  in  contact  with 
highly  concentrated  nitric  acid,  but  as  the  latter  by  the 
absorption  of  water  becomes  in  a  short  time  less  concen- 
trated, mixtures  of  nitric  and  sulphuric  acids  are  generally 
used  as  nitrating  fluids.  Sulphuric  acid  being  a  body 
which  fixes  water  with  great  energy,  its  purpose  in  this 
case,  is  to  absorb  the  water  which  is  formed,  so  that  the 
concentration  of  the  nitric  acid  remains  the  same. 

This  assumption,  however,  does  not  agree  with  the  facts 
which  have  been  established  in  reference  to  the  behavior  of 
cellulose  towards  mixtures  of  very  varying  quantities  of 
nitric  and  sulphuric  acids.  From  investigations  of  the  pro- 
ducts thus  formed  it  would  appear  that  the  kind  of  combi- 
nation formed  is  very  materially  influenced  by  the  larger 
or  smaller  quantity  of  sulphuric  acid  present. 

For  an  explanation  of  these  facts  we  are  indebted  to  the 
thorough  investigations  made  conjointly  by  G.  Lunge  and 
E.  Weintraub,  and  the  points  of  practical  importance  for 
the  preparation  of  nitro-cellulose  will  here  be  briefly  given. 

The  larger  the  quantity  of  sulphuric  acid  in  the  nitrating 
fluid  in  comparison  with  that  of  nitric  acid,  the  more  slowly 
the  entire  process  is  completed.  By  using  J  part  of  sul- 
phuric acid  to  1  part  of  nitric  acid,  reaction  is  complete  in 
half  an  hour.  (It  may  be  here  remarked  that  the  course  of 
the  reaction  may  be  measured  by  the  quantity  of  nitrogen 
present  in  the  newly-formed  nitro-product.)  With  the  use 
of  a  mixture  of  3  parts  of  sulphuric  acid  and  1  part  of 
nitric  acid  the  content  of  nitrogen  in  the  product  is  in  the 


164  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

course  of  half  an  hour  much  lower  than  with  the  use  of  the 
previous  mixture.  If,  finally,  a  fluid  of  8  parts  sulphuric 
acid  and  1  part  nitric  acid  be  employed,  reaction  is  not 
complete  even  in  a  month. 

With  a  slower  course  of  reaction  the  content  of  nitrogen 
in  the  product  is  also  changed,  i.  e.,  with  an  increasing 
content  of  sulphuric  acid  in  the  nitrating  fluid,  final  pro- 
ducts are  obtained  which  contain  less  nitrogen  than  with 
the  use  of  a  smaller  quantity  of  sulphuric  acid. 

The  presence  of  a  very  large  quantit}^  of  sulphuric  acid 
(more  than  8  to  1)  in  the  nitrating  fluid  appears  to  be  the 
reason  why,  even  after  remaining  for  so  long  a  time  in  con- 
tact with  the  fluid,  a  certain  quantity  of  the  cellulose  itself 
remains  unchanged  and  is  not  converted  into  a  nitro- 
compound.  In  our  opinion,  an  explanation  of  this  phe- 
nomenon may  be  found  in  the  fact  that,  in  the  commence- 
ment of  the  operation,  certain  fibres  of  the  cellulose  are 
already  changed  by  the  sulphuric  acid  in  a  manner  similar 
to  that  when  cellulose  is  converted  into  vegetable  parchment, 
and  thus  become  inaccessible  to  the  action  of  the  nitric  acid. 
That  the  presence  of  a  larger  quantity  of  sulphuric  acid  in 
the  nitrating  fluid  exerts  a  material  influence  upon  the 
physical  structure  of  the  product  has  been  confirmed  by  the 
investigations  above  referred  to. 

With  the  use  of  a  nitrating  fluid  containing  but  a  small 
quantity  of  sulphuric  acid — about  ^  to  J  of  the  weight  of 
nitric  acid — a  product  is  obtained  which  possesses  greater 
strength  than  the  cellulose  originally  used,  the  fibres  ap- 
pearing strongly  contracted.  If,  on  the  other  hand,  fluids 
rich  in  sulphuric  acid  (7  to  1  upwards)  are  employed,  the 
dry  product  represents  a  finely-fibered  powder. 

The  process  of  nitration  is  completed  the  more  rapidly 
the  higher  the  temperature  of  the  fluids  is,  it  being  effected 
in  the  shortest  time  at  between  140°  and  176°  F.  In  prac- 
tice it  is,  however,  not  feasible  to  work  with  such  a  high 
temperature,  the  yield  of  mtro-cellulose  becoming  con- 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  165 

stantly  smaller  with  an  increasing  temperature,  and  a  con- 
siderable portion  of  the  substance  passing  into  solution. 

When  working  with  a  nitrating  fluid  heated  to  140°  F., 
nitration  may  be  considered  complete  in  half  an  hour. 
The  loss  in  cellulose  was  found,  in  this  case,  to  amount  to 
1.95  per  cent.  By  leaving  the  finished  product  in  the  hot 
fluid,  5.67  per  cent,  of  it  was  in  the  course  of  4J  hours 
again  destroyed. 

With  the  use  of  a  fluid  heated  to  176°  F.,  the  destructive 
processes  became  still  more  conspicuous,  and  nitration,  in 
this  case,  was  generally  complete  in  less  than  a  quarter  of 
an  hour.  The  loss  in  cellulose  amounted  to  6.25  per  cent., 
increasing  in  half  an  hour  to  27.45  per  cent.,  and  in  three 
hours  to  52.76  per  cent. 

By  nitration  at  higher  temperatures,  a  change  in  the 
structure  of  the  nitro-cellulose  takes  place,  it  becoming 
short-fibered  and  brittle,  and  the  product  prepared  under 
these  conditions  appears,  after  drying,  as  a  finely-fibered 
powder. 

Towards  polarized  light,  nitro-cellulose  acts  in  a  very 
peculiar  manner,  it  having  been  asserted  by  some  investi- 
gators that  the  different  degrees  of  nitration  may  be  recog- 
nized from  the  appearance  of  the  fibres  when  observed  in 
polarized  light.  However,  Lunge  and  Weintraub  specify 
this  as  not  being  pertinent. 

In  polarized  light  the  highest  degrees  of  nitration  appear 
pale  to  dark  blue.  However,  important  information  re- 
garding the  presence  of  unchanged  cellulose  is  gained  by 
examining  nitro-cellulose  in  polarized  light,  the  unchanged 
cellulose  appearing  pale  yellow  to  reddish,  and  lights  up 
more  than  nitro-cellulose.  It  is,  however,  impossible  to 
determine  from  the  picture  in  the  polarizing  microscope 
the  quantity  of  non-nitrated  cellulose.  If  the  latter 
amounts  to  only  5  per  cent.,  a  large  portion  of  the  field  of 
vision  appears  already  of  a  yellow  color,  and,  if  the  content 
of  cellulose  increases  to  10  or  15  per  cent.,  it  is  no  longer 


166  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

possible  to  observe  the  polarizing  phenomena  of  the  nitro- 
cellulose, they  being  completely  hid  by  those  of  the  cellulose. 

Although  the  disclosures  afforded  by  observing  the  fibres 
under  the  polarizing  microscope  are  quite  uncertain,  they 
may  nevertheless  be  utilized  for  gaining  information  in  re- 
gard to  the  state  of  nitration  as,  for  instance,  is  done  by 
Chardonnet,  in  testing  the  nitro-cellulose  which  is  to  be 
used  for  the  preparation  of  artificial  silk  (see  later  on). 
When  the  field  of  view  shows  exclusively  blue-appearing 
fibres,  and  no  yellow  ones  can  be  seen,  it  is,  at  all  events,  a 
proof  that  the  total  quantity  of  cellulose  used  has  been 
nitrated,  and  that  the  product  is  very  likely  completely 
soluble. 

In  practice  two  main  objects  are  especially  to  be  attained 
in  the  preparation  of  nitro-cellulose,  namely,  the  product 
must  either  be  explosive  to  the  highest  degree,  i.  e.,  gun- 
cotton  in  the  actual  sense  of  the  word,  or  it  must  dissolve 
in  solvents  without  leaving  a  residue,  the  term  collodion 
cotton  being,  in  the  latter  case,  generally  applied  to  the 
product. 

In  conducting  the  nitration  of  cellulose  it  is  scarcely 
probable  that  a  product  is  obtained  which  is  in  accordance 
with  a  positively  determined  combination,  i.  e.,  a  nitro-cel- 
lulose of  positively  determined  composition,  the  result  being, 
on  the  contrary,  always  mixtures  of  various  degrees  of  ni- 
tration with  more  or  less  changed  cellulose. 

For  practical  purposes  two  products  of  different  proper- 
ties come  chiefly  into  question,  namely,  on  the  one  hand, 
the  preparation  of  a  nitro-cellulose  which,  in  exploding, 
produces  the  greatest  dynamic  effect  and  is  suitable  for  the 
manufacture  of  blasting  gelatine,  and  on  the  other,  the  pro- 
duction of  a  nitro-cellulose  which  can  be  completely  dis- 
solved. The  latter  product  has  attained  great  importance 
for  photographic  use,  and  the  manufacture  of  artificial  silk. 

Information  regarding  the  composition  of  nitro-cellulose 
produced  by  a  certain  process  is  sought  to  be  obtained  by 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).  167 

establishing  the  quantities  of  nitrogen  contained  in  them. 
While  the  French  chemists  calculate  the  nitrogen  in  the 
form  of  nitric  oxide  which  can  be  obtained  from  1  gramme 
substance  (reduced  to  0°  and  760  millimeters  height  of  bar- 
ometer), the  English  and  German  chemists  give  the  content 
of  nitrogen  directly  in  per  cent. 

Conjointly  with  J.  Bebie,  G.  Lunge  has  recently  occupied 
himself  with  the  composition  and  properties  of  the  various 
nitro-celluloses,  and  in  the  commencement  of  a  very  full 
article  published  in  the  "  Zeitschrift  fur  angewandte 
Chemie,"  1901,  these  investigators  give  the  relation  between 
the  modes  of  determination  adopted  by  the  French  and 
German  chemists,  as  shown  in  the  table  below,  which  af- 
fords a  ready  comparison  between  the  two  methods  of  ex- 
amination. 


Name. 

Formula. 

Ccm.  nitric 
oxide  (NO) 
in  1  g. 

Per  cent, 
nitrogen  (N) 
inl  g. 

Dodeca- 
Endeca- 
Deca- 
Ennea- 
Octo- 
Hepta- 
Hexa- 
Penta- 
Tetra- 

1 

3 

'1 
| 

C24H2808(N03)12 
C24H2909(N03)n 

C"H^O;°(N03)910 
C24H32012(NO,)8 
C24H33018(N03)7 

C244H3350;5(N03)86 
C24H36016(NOS)4 

226.17 
215.17 
203.35 
190.75 
177.19 
162.36 
145.93 
127.91 
107.81 

14.14 
13.47 
12.75 
11.96 
11.11 
10.18 
9.15 
8.62 
6.76 

According  to  the  investigations  of  the  above-mentioned 
scientists,  the  degrees  of  nitration  from  tetra-nitro-cellulose 
to  deca-nitro-cellulose  can  only  be  obtained  by  treating  cot- 
ton with  nitric  acid,  while  for  still  higher  degrees  of  nitra- 
tion, mixtures  of  nitric  and  sulphuric  acids  have  to  be 
employed.  Since  in  the  preparation  of  nitre-cellulose  on  a 
large  scale,  mixtures  of  nitric  and  sulphuric  acids  are  always 
used,  such  mixtures  were  almost  exclusively  employed  in 
the  above  investigations. 


168 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


The  influence  exerted  by  the  content  of  water  in  the  acid 
mixture  upon  the  process  of  nitration  is  shown  by  the  table 
below  : 


bb 

g 

"o 

Nitrating  mixtures.    ul  ft 

rH 

A 

1 

tf 

+r, 

.S  J 

. 

t 

Ccm.NO  ii 

Per  cent.  ] 
1* 

pi 

& 

!3 

Sulphuric 
acid 
S04H2. 

Nitric 
acid 
HN03. 

Water 
H20. 

217.73 

13.65 

1.50 

177.5 

45.31 

49.07 

5.62 

210.68 

13.21 

5.40 

176.2 

42.61 

46.01 

11.38 

203.49 

12.76 

22.00 



41.03 

44.45 

14.52 

200.58 

12.58 

60.00 

167.0 

40.68 

43.85 

15.49 

196.35 

12.31 

99.14 

159.0 

40.14 

43.25 

16.61 

192.15 

12.05 

99.84 

153.0 

39.45 

42.73 

17.82 

184.78 

11.59 

100.02 

156.5 

38.95 

42.15 

18.90 

174.29 

10.93 

99.82 

144.2             38.43 

41:  31 

20.26 

155.73 

9.76 

74.22 

146.0            37.20 

40.30 

22.50 

148.51 

9.31 

1.15 

138.9 

36.72 

39.78 

23.50 

133.94 

8.40 

0.61 

131.2 

35.87 

38.83 

25.30 

103.69 

6.50 

1.73 

— 

34.41 

31.17 

28.42 

The  considerable  differences  appearing  in  the  degrees  of 
nitration  between  the  soluble  and  insoluble  parts  might  be 
explained  by  the  dilution  of  the  nitrating  mixtures  which 
occurs  in  the  course  of  reaction,  this  dilution  being  due  to 
the  withdrawal  of  nitric  acid  and  to  the  water  formed  by  the 
process  itself.  It  having,  however,  been  established  by  the 
investigations  that  a  difference  of  a  few  per  cent,  of  water 
suffices  to  produce  degrees  of  nitration  which  differ  consid- 
erably one  from  the  other,  it  follows  that  a  uniform  product 
is  never  obtained,  but  always  a  mixture  of  different  degrees 
of  nitration.  To  prevent  this  as  much  as  possible  in  prac- 
tice, the  operation  should  be  so  conducted  that  the  quantity 
of  nitrating  fluid  is  very  large  in  proportion  to  cotton,  the 
effect  of  dilution  being  then  less  pronounced. 

If  the  nitrating  mixture  contains  16.6  per  cent,  of  water 
a  completely  soluble  product  belonging  to  the  group  of 
actual  collodion  cottons  is  obtained.  From  18  per  cent. 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  169 

up,  the  content  of  nitrogen  decreases  very  rapidly  with  the 
increase  in  the  content  of  water. 

The  entire  group  of  soluble  nitro-celluloses  between  170 
and  196  cubic  cm.  is  defined  by  a  content  of  water  which 
only  amounts  to  4  per  cent.  (16.5  to  20.5  per  cent.). 
Between  7  and  8  lies  the  odo-nitro-cellulose  with  a  content  of 
177.2  cubic  cm.  of  nitrogen  which  may  be  designated  as  the 
typical  soluble  nitro-cellulose — the  actual  collodion  cotton.  This 
product  is  always  obtained  by  working  with  a  nitrating  mixture 
which  contains  19.4.®  per  cent,  of  water. 

This  statement  is  of  great  importance  for  the  practice,  it 
pointing  out  the  way  in  which  the  material  required  for 
the  production  of  collodion  for  photographic  purposes,  as 
well  as  for  the  manufacture  of  artificial  silk,  can  be  pre- 
pared. According  to  statements  made  in  this  direction  re- 
garding the  manufacture  of  artificial  silk  according  to 
Chardonnet,  a  nitrating  fluid  composed  of  85  parts  of  sul- 
phuric acid  and  15  parts  of  fuming  nitric  acid,  is  for  4  to  6 
hours  allowed  to  act  upon  cotton.  However,  several  chem- 
ists in  working  according  to  this  direction  obtained  no 
adequate  results,  and  even  with  the  use  of  a  higher  temper- 
ature, the  results  were  not  more  favorable,  as  shown  in  the 
following  table  : 


Temperature. 

Duration  of 
nitration. 

Ccm.  NO  in 
1  gramme. 

Solubility. 

Yield. 

86°  F. 
104°  F. 

4  hours. 
7  hours. 

199.89 
209.90 

17.14 
15.54 

160.2 
143.1 

The  solubility  of  the  products  which  were  last  obtained 
is  only  slight,  nitration,  however,  being  complete,  and  in 
polarized  light  all  the  fibres  appear  of  a  slightly  steel-blue 
color.  However,  it  may  in  this  case  be  remarked  that  with 
nitro-cellulose  with  a  content  of  nitrogen  below  190  cubic 
cm.,  blue  lighting  up  could  never  be  observed. 

The  solubility  of  nitro-celluloses  with  a  content  below 


170 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


160  cubic  cm.  decreases,  the  degrees  of  nitration  from  hexa- 
nitro-cellulose  downward  being  insoluble  in  ether-alcohol. 
According  to  Eders'  investigations,  which  chiefly  referred  to 
the  preparation  of  collodion-cottons,  di-nitro-cellulose  and 
tri-nitro-cellulose  are  soluble  combinations.  (See  soluble 
gun-cotton  or  collodion-cotton  later  on). 

With  a  still  greater  increase  in  the  content  of  water,  the 
nitrating  effect  decreases  very  much,  and  the  entire  process 
seems  to  be  turned  in  another  direction,  products  possess- 
ing the  properties  of  oxy-cellulose  being  now  formed.  They 
are  soluble  in  dilute  alkalies  and  can  be  again  separated 
from  these  solutions  by  acids  or  alcohol.  When  brought 
in  contact  with  basic  coloring  matters,  they  acquire  an  in- 
tense coloration,  reduce  Fehling's  solution,  and  yield  com- 
binations of  phenyl-hydrazine. 

The  effect  of  higher  temperatures  such  as  are  used  in  the 
preparation  of  collodion  cottons  is  shown  by  the  summary, 
given  below,  of  a  few  experiments  made  in  this  respect  with 
the  use  of  a  nitrating  fluid  which  contained  18.9  per  cent, 
of  water. 


Duration  of 
nitration. 

Temperature 
Degrees  F. 

Ccm.  NO 
in  1  g. 

Solubility  in 
ether-alcohol. 

Yield. 

4  hours. 

62.6 

183.54                  95.60 

155.1 

24  hours. 

62.6 

184.78 

99.81 

156.2 

4  hours. 

104 

183.40 

99.58 

148.1 

4  hours. 

140 

172.48 

99.82 

52.0 

£  hour. 

140 

182.80 

99.71 

146.7 

As  shown  by  these  figures,  nitration  was  complete  in  4 
hours  at  the  ordinary  temperature  and  the  yield  was  greater 
than  at  104°  F.,  but  the  product  dissolved  with  greater  dif- 
ficulty and  less  completely  in  the  mixture  of  ether  and 
alcohol.  By  increasing  the  temperature  to  140°  F.,  partial 
denitration  took  place  rapidly.  After  4  hours  the  content 
of  nitrogen  had  dropped  to  172.48  cubic  cm.  By  allowing 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).  171 

the  acid  to  act,  at  such  a  high  temperature,  only  for  a  short 
time,  for  instance,  J  hour,  nitration  is  complete,  but  if  this 
time  be  exceeded,  a  decrease  in  the  content  of  nitrogen  im- 
mediately takes  place. 

Simultaneously  with  denitration,  the  structure  of  the  cot- 
ton is  also  completely  destroyed ;  it  crumbles  to  a  delicate 
paste,  a  pulverulent  mass  remaining  behind  after  drying. 
The  structure  of  the  nitrated  cotton  is  also  affected  by  the 
content  of  water  in  the  nitrating  fluid.  Up  to  a  content  of 
water  of  15  per  cent.,  scarcely  any  change  in  the  structure 
is  observed,  but  from  18  per  cent,  up,  the  fibres  are  some- 
what contracted  and  the  peculiar  twist  characteristic  of 
cotton  disappears.  With  a  still  larger  content  of  water  the 
structure  of  the  fibres  is  almost  completely  destroyed  ;  the 
cavity  is  torn  open,  and  the  fibres  crumble  to  small  frag- 
ments which  felt  together  in  knotty  masses.  The  destructive 
effect  is  greatest  when  the  content  of  water  reaches  23  to 
25  per  cent. 

Although  all  the  mtro-celluloses  up  to  the  deca-combina- 
tion  can  be  produced  with  the  use  of  nitric  acid  alone,  a 
mixture  of  nitric  and  sulphuric  acids  is  generally  used  for 
the  preparation  of  collodion  cotton,  a  saving  of  nitric  acid 
being  thereby  effected  and  the  time  of  reaction  shortened. 
With  the  use  of  a  mixture  of  1  nitric  acid  to  3  sulphuric 
acid  the  following  figures  were  obtained  : 


-J 

Ccm.NO.  in 
lg- 

Per  cent.  N. 

Solubility 
in  ether- 
alcohol. 

Yield. 

Proportion 
of  cellulose 
to  nitric 
acid. 

t 

1 

210.69 

13.21 

3.20 

174 

2 

198.10 

12.42 

98.70 

160 

1  :30 

3 

186.00 

.    11.72 

99.28 

157 

4 

174.81 

10.96 

99.50 

148 

5 

187.30 

11.74 

99.98 

159 

1:12 

6 

173.83 

10.90 

99.20 

149 

172 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


The  nitrating  fluids  used  in  these  experiments  were  com- 
posed as  follows : 


Experiment. 

1 

2 

3 

4 

5 

6 

H2S04  .... 
HNO2  .... 
H2O   

62.18 
21.91 
15.91 

61.53 
2002 
18.45 

60.30 
19.71 
19.99 

38.88 
19.60 
21.52 

59.77 
20.94 
19.29 

58.34 
20.62 
21.04 

The  product  obtained  by  experiment  No.  2  closely  re- 
sembles, as  regards  its  content  of  nitrogen,  as  well  as  its 
solubility,  the  preparation  to  which  the  term  pyro-collodion 
has  been  applied  by  Mendelejeff. 

The  final  results  of  further  experiments  made  with  the 
use  of  nitric  and  sulphuric  acids  in  the  proportions  of  1  : 4 
and  1 :  5  are  given  in  the  table  below  : 


1 
a 

Ccm.NO  in 

Per  cent.  N. 

Yield. 

Proportion 
of  HNO3  to 

Proportion 
of  cellulose 

1 

g- 

H2SO4. 

to  HNO3. 

1 

i 

192.65 

12.08 

163 

2 

179.10 

11.23 

153 

1  :3.8 

1:30 

3 

187.58 

11.76 

156 

4 

175.23 

10.99 

151 

1:12 

5 

198.32 

12.42 

167 

6 

185.89 

11.66 

158 

1  :30 

7 

168.00 

10.53 

140 

1  :5 

1:8 

8 

149.12 

9.35 

— 

The  composition   of  the  nitrating  fluids  used  in  these 
experiments  was  as  follows : 


Experiment. 

1  and  3 

2  and  4 

5 

6 

7 

8 

H2SO,  .... 
HN03  .... 
HoO. 

63.84 
16.96 
18.20 

62.52 
16.46 
21.02 

67.60 
13.66 
18.74 

66.37 
13.04 
20.59 

64.85 
14.90 
20.25 

64.11 
13.62 

22.27 

NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).  173 


The  temperature  used  in  all  the  experiments  was  the 
ordinary  one  of  a  room,  and  the  duration  of  nitration  24 
hours. 

With  the  use  of  nitrating  fluids,  the  acid  proportions  of 
which  were  1  :  3,  1  :  3.8,  and  1  :  5,  a  few  experiments  were 
made  at  a  higher  temperature,  and  at  95°  F.,  after  allowing 
the  acid  mixture  to  act  for  only  two  hours,  the  same  pro- 
ducts as  under  the  above-mentioned  conditions  were  ob- 
tained. 

When  carrying  on  nitration  according  to  a  determined 
rule,  attention  has  to  be  chiefly  directed  to  the  content  of 
water  in  the  nitrating  fluid,  the  quality  of  the  products 
obtained  being  less  affected  by  the  larger  or  smaller  quan- 
tity of  sulphuric  acid.  A  special  series  of  experiments,  in 
which  the  proportion  between  nitric  acid  and  water  was 
strictly  maintained,  while  the  quantity  of  sulphuric  acid 
was  changed,  showed  that  the  products  obtained  with  dilute 
mixtures  have  to  be  considered  as  nitro-oxycelluloses, 
or  as  mixtures  of  nitro-celluloses  with  nitro-oxycelluloses. 
Further  experiments  showed : 


Nitrating  fluid. 

Ccm.NO  in 

Per  cent.  N. 

Yield. 

g' 

H2SO<. 

HN03. 

H20. 

217.26 

13.62 

173 

60.00 

27.43 

12.57 

219.28 

13.75 

174 

62.10 

25.79 

12.11 

220.66 

13.83 

175 

62.95 

24.95 

12.10 

219.34 

13.75 

175 

63.72 

25.31 

10.97 

218.73 

13.71 

175 

64.56 

24.65 

10.79 

Thus,  products  were  obtained  which,  as  regards  their 
content  of  nitrogen  (up  to  13.83  per  cent.),  more  closely 
approach  hexa-nitro-cellulose  (14.14  per  cent.)  than  all 
previous  ones  produced  with  nitric  and  sulphuric  acids. 
The  feature  of  this  experiment  of  value  in  practice  is  the 
fact,  that  nitro-celluloses  with  a  high  content  of  nitrogen 


174  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

may  be  obtained  with  acid  mixtures  quite  rich  in  water. 
By  a  series  of  special  experiments  it  was  shown  that  a  con- 
tent within  very  wide  limits  of  hyponitric  acid  in  the  nitric 
acid  exerts  no  influence  whatever  upon  the  course  of  the 
process. 

The  valuable  investigations  of  G.  Lunge  and  J.  Bebie 
conclude  with  giving  analyses  of  various  nitro-celluloses. 
Samples  of  collodion  cotton  were  first  examined.  One  of 
them  marked  A,  came  from  a  Belgian  factory,  and  is  used 
for  the  preparation  of  blasting  gelatine,  while  the  other, 
marked  B,  from  a  factory  at  Breitenbach  near  Ziirich,  is 
manufactured  for  the  purpose  of  preparing  artificial  silk. 

Sample  A  showed  in  1  g.  196.7  Cc.NO  =  12.33  per  cent. 
N,  a  solubility  in  ether-alcohol  of  95.49  per  cent.,  and  an 
exploding  point  of  389.3°  F.,  after  heating  during  4'  46". 

Sample  B  showed  an  exploding  point  of  386.6°  F.  after 
heating  during  4'  46".  The  most  highly  nitrated  actual 
gun-cotton  from  the  Eidgenoessischen  Munitionsfabrik  at 
Thun  proved,  in  regard  to  its  explosibility,  almost  identical 
with  the  less  highly  nitrated  collodion  cotton.  In  other 
samples,  collodion  cotton  also  showed  a  somewhat  higher 
exploding  point  than  well-washed  gun-cotton,  while  prepar- 
ations not  thoroughly  washed  exploded  at  much  lower  de- 
grees of  heat. 

PREPARATION    OF    GUN-COTTON. 

The  first  requisite  for  the  production  of  gun-cotton  which 
will  in  every  respect  come  up  to  the  demands  made  on  it, 
is  the  presence  of  entirely  pure  cellulose,  either  purified  cot- 
ton being  used,  or  more  rarely  a  fine  quality  of  paper  con- 
taining only  cellulose.  However,  the  cost  of  production 
being,  in  the  latter  case,  much  higher  than  with  cotton,  the 
latter  is  always  used  for  manufacturing  on  a  large  scale. 

Raw  cotton  contains  always  certain  quantities  of  fat,  wax- 
like  substances,  and  coloring  matter.  To  free  it  from  these 
bodies,  it  is  first  boiled  with  weak  soda  lye  in  large  wooden 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  175 

vats  with  the  use  of  steam,  then  freed  from  lye  by  means  of 
a  centrifugal,  and  finally  washed  with  water  until  all  alka- 
line reaction  has  disappeared.  It  is  then  bleached  with 
chlorine,  washed  in  acidulated  water,  then  in  pure  water, 
and  is  finally  freed  from  water  in  a  centrifugal,  and  dried. 
The  dry  cotton  is  stored,  carefully  protected  from  dust,  till 
it  is  to  be  treated  with  nitric  acid.  Loose,  as  well  as  spun, 
cotton  may  be  subjected  to  nitration,  but  many  manufactur- 
ers prefer  to  use  loosely-spun  cotton,  the  hanks  being  more 
readily  handled  than  the  loose,  bulky  material. 

ACID  USED  FOR  NITRATION. 

The  conversion  of  cellulose  into  gun-cotton  may  be  ef- 
fected by  treating  it  with  concentrated  nitric  acid  alone. 
However,  this  process  is  not  expedient,  since  by  the  absorp- 
tion of  water  the  nitric  acid  soon  becomes  diluted  to  such  an 
extent  that  it  has  to  be  replaced  by  fresh  acid.  At  present 
mixtures  of  concentrated  nitric  and  sulphuric  acids  are  gen- 
erally used,  the  latter  acid  acting  as  a  water-attracting  body, 
and  the  concentration  of  the  nitric  acid  is  thus  for  a  longer 
time  maintained  at  the  required  degree.  Nitration  was 
formerly  also  effected  by  introducing  thoroughly-dried  and 
finely-pulverized  saltpetre  into  concentrated  sulphuric  acid, 
a  highly  concentrated  nitric  acid  being  thus  obtained.  How- 
ever, many  obstacles  being  met  in  completely  removing  the 
potassium  sulphate,  which  dissolves  with  some  difficulty, 
from  the  gun-cotton  by  washing,  this  process  has  been  en- 
tirely abandoned,  and  at  present  mixtures  of  the  two  acids 
are  only  used. 

For  the  manufacture  of  very  explosive  products,  nitric 
acid  as  concentrated  as  possible  (specific  gravity  1.500) 
should  be  used,  but  for  readily  soluble  products,  nitric  acid 
of  specific  gravity  1.400,  and  containing  in  round  numbers 
65  per  cent,  of  nitric  mono-hydrate,  suffices.  The  nitric 
acid  must  be  entirely  free  from  foreign  bodies,  and  contain 
but  a  small  quantity  of  hyponitric  acid,  the  product  stand- 
ing next  to  it. 


176  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

The  sulphuric  acid  to  be  used  is  the  highly  concentrated 
white  acid  of  commerce.  It  should  be  free  from  iron,  and 
contain  but  a  very  small  quantity  (not  more  than  0.1  per 
cent.)  of  arsenic. 

Because  of  their  properties,  the  storage  of  the  acids  is 
connected  with  some  difficulties.  The  nitric  acid  should 
be  kept  in  the  carboys  in  which  it  is  shipped  from  the  fac- 
tory until  it  is  to  be  mixed  with  the  sulphuric  acid.  The 
store-room  in  which  the  carboys  are  kept  should  be  fire- 
proof, so  that  in  case  one  of  them  bursts,  and  the  straw  in 
the  basket  used  for  packing  ignites,  the  flames  cannot 
spread.  The  carboys  should  be  placed  so  that  a  bursted 
carboy  can  be  drawn  by  means  of  a  hook  into  the  centre  of 
the  store-room,  and  the  floor  of  the  latter  so  planned  that 
the  acid  can  run  off  into  a  pit.  Only  after  the  burning 
basket  has  been  entirely  consumed,  and  the  room  has  been 
thoroughly  aired,  can  the  latter  be  again  entered.  Pure 
aluminium  being  indifferent  towards  concentrated  nitric 
ficid,  boiler-like,  closed  vessels  of  this  material  might  be 
used  for  storing  it. 

Sulphuric  acid  of  fixed  concentration  (not  below  1.600 
specific  gravity),  as  otherwise  hydrogen-gas  would  be 
evolved,  may  be  kept  in  iron  vessels,  old  steam  boilers 
being  frequently  used  for  this  purpose.  Iron  being  brought 
into  a  passive  state  by  concentrated  nitric  acid,  nitration 
may  be  effected  in  cast-iron  vessels  furnished  with  a  con- 
trivance by  means  of  which  a  large  portion  of  the  absorbed 
fluid  may  be  withdrawn  when  the  cotton  has  been  suffi- 
ciently treated. 

When  working  on  a  very  large  scale,  stoneware  vessels 
standing  in  a  large  trough  filled  with  water  to  prevent 
strong  heating,  are  preferably  used.  For  introducing  and 
lifting  out  the  cotton  a  strong  glass-rod  bent  into  a  hook  on 
one  end  is  employed. 

The  nitrating  fluid  is  the  mixture  of  nitric  and  sulphuric 
acids,  in  which  the  cotton  to  be  nitrated  is  immersed.  It 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).  177 

depends  on  the  proportions  in  which  the  two  acids  are 
mixed,  whether  a  very  explosive,  but  only  slightly  soluble, 
mass — gun-cotton  in  the  actual  sense  of  the  word — is  ob- 
tained, or  a  product  only  slightly  explosive,  but  readily 
soluble,  to  which  the  term  collodion-cotton  may  be  applied. 
The  proportions  for  both  these  products,  as  determined  by 
numerous  experiments  in  practice,  are  as  follows : 

For  explosive  gun-cotton :  1  part  nitric  acid  and  3  parts 
sulphuric  acid. 

For  soluble  gun-cotton :  Equal  parts  of  nitric  acid  with  75 
per  cent,  of  nitric  anhydride  and  concentrated  sulphuric 
acid  with  96  per  cent,  sulphuric  anhydride. 

CONDITION  OF  THE  NITRATING  FLUID. 

The  constancy  of  the  composition  of  the  acid  mixture  is 
of  great  importance  for  the  production  of  a  uniform  pro- 
duct, whether  explosive  or  soluble.  However,  in  reality, 
it  is  quite  a  difficult  matter  to  maintain  this  state  of  the 
acid  mixture,  because  during  nitration  water  is  always 
formed,  causing  a  dilution  of  the  acid.  Theoretically,  a 
certain  quantity  of  acid  could  be  used  at  one  time,  but  as 
this  is  impossible  in  practice,  an  effort  has  to  be  made  to 
maintain  as  long  as  possible  the  concentration  of  the  acid 
within  certain  limits.  It  would,  therefore,  seem  advisable 
to  use  nitrating  vessels  of  comparatively  large  size,  the  ad- 
vantage gained  thereby  being  that  the  concentration  of  the 
acids  is  not  to  any  considerable  extent  reduced  by  successive 
nitrations.  By  successive  immersions  of  fresh  quantities  of 
cotton  in  the  nitrating  vessel,  the  level  of  the  fluid  will  fall, 
but  if  it  be  restored  to  its  original  height,  by  a  workman 
allowing  fresh  acid  mixture  kept  in  readiness  to  run  in,  the 
dilution  of  the  acid  in  the  nitrating  vessel  is  decreased  by 
this  addition  of  concentrated  acids. 

In  this  manner  the  operation  may  for  a  long  time  be 
continued  without  the  necessity  of  removing  the  acid  mix- 
ture on  account  of  its  containing  too  much  water.     How-. 
12 


178  CELLULOSE,   AND    CELLULOSE    PRODUCTS. 

ever,  as  a  rule,  the  acid  has  to  be  earlier  removed  for  another 
reason.  Many  fine  fibres  of  gun-cotton  collect  gradually  in 
the  fluid  in  the  nitrating  vessel,  and  when  immersing  fresh 
cotton,  adhere  so  firmly  to  the  latter  as  to  greatly  retard 
the  penetration  of  the  nitrating  fluid.  This  may  to  some 
extent  be  remedied  by  taking  the  acid  from  the  nitrating 
vessel  and  filtering  it  through  glass-wool  in  a  stoneware 
filter,  or  by  bringing  it  into  a  tall  reservoir  and  allowing  it 
to  stand  quietly  until  the  delicate  fibres  have  deposited  on 
the  bottom  and  the  supernatant  acid  is  clear. 
.  The  nitrating  fluids,  which  have  been  removed  from  the 
nitrating  vessels,  are  always  regenerated  to  be  again  util- 
ized. In  doing  this  it  is  absolutely  necessary  to  determine 
by  accurate  analysis  the  quantities  of  nitric  and  sulphuric 
acids,  as  well  as  of  water,  contained  in  the  fluids.  Based 
upon  this  analysis,  it  can  then  be  calculated  how  much  of 
the  most  highly  concentrated  acids  has  to  be  added  to  re- 
store the  proportion  between  the  acids  as  required  for 
nitration. 

Since  by  constant  regeneration  an  excessive  quantity  of 
exhausted  acid  would  in  time  be  obtained,  fuming  sulphuric 
acid  is  frequently  used  in  place  of  ordinary  sulphuric  acid, 
and  when  sulphur  trioxide  can  be  obtained  in  commerce  at 
suitable  prices,  its  use  for  the  regeneration  of  the  acid  mix- 
ture may  be  recommended.  As  regards  the  nitric  acid  to 
be  employed,  it  need  scarcely  be  mentioned  that  it  should 
be  as  highly  concentrated  as  possible. 

EXECUTION    OF    NITRATION. 

Nitration  of  the  cotton  may,  as  previously  mentioned,  be 
effected  in  stoneware  vessels  as  well  as  in  a  cast-iron  appa- 
ratus. In  any  case  the  vessels  must  be  placed  in  a  room 
provided  with  contrivances  for  carrying  off  the  gases  evolved 
during  nitration,  they  having  a  deleterious  effect  upon  the 
respiratory  organs  of  the  workmen.  Hence  a  ventilating 
hood  connecting  above  with  a  pipe  is  placed  over  each 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).          179 

nitrating  vessel.  These  pipes  terminate  in  a  joint  pipe, 
into  which  air  is  constantly  sucked  by  a  ventilating  con- 
trivance. In  smaller  plants  this  air  is  forced  through  a 
layer  of  red-hot  coal,  the  products  of  decomposition  of  the 
nitric  acid  being  thus  rendered  innocuous  for  the  neighbor- 
hood. In  larger  factories  it  is  more  economical  to  conduct 
the  air  loaded  with  products  of  decomposition  of  the  nitric 
acid  into  a  condensing  tower  and  utilize  it  again  for  nitric 
acid. 

Fig.  33  represents  an  iron  nitrating  apparatus  so  arranged 

FIG.  33. 


that  the  gun-cotton  nitrated  in  it  can  at  the  same  time  be 
quite  vigorously  pressed  out.  The  cast-iron  trough  K,  ob- 
liquely cut  off  on  the  side  turned  towards  the  workmen,  is 
surrounded  by  a  vessel  T,  through  which  water  runs  con- 
stantly, passing  in  at  0  and  passing  out  at  01.  The  object 
of  this  arrangement  is  to  carry  on  the  operation  always  at 
the  same  temperature,  and  therefore  hot  or  cold  water  is, 
according  to  the  season  of  the  year,  conducted  through  T. 


180  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

The  contrivance  for  pressing  out  the  nitrated  cotton  con- 
sists of  a  grate-like  iron  plate  R,  upon  which  can  be  placed 
a  solid  iron  plate  P,  which  is  provided  with  a  vertical  part 
Cl  serving  as  the  fulcrum  of  a  lever.  When  the  cotton 
just  lifted  out  from  the  acid  mixture  is  spread  out  upon  the 
grate-like  plate  by  placing  the  solid  plate  upon  it,  it  can 
be  vigorously  pressed  by  means  of  the  lever,  the  acid 
pressed  out  running  back  into  the  vessel  K. 

The  plate  P  is  connected  with  the  vertical  part  C.  To 
the  latter  is  secured  a  chain  which  runs  over  a  pulley  and 
carries  on  the  upper  part  the  weight  G.  By  this  weight  the 
plate  P  is  raised  to  the  pivot  z  z,  so  that  the  cotton  lifted 
out  from  the  nitrating  vessel  can  be  placed  upon  the  grate- 
like  plate  R,  and  pressed  by  placing  in  position  the  lever 
which  revolves  around  Cl  the  cotton  being  thus  compressed 
and  the  fluid  pressed  out  falls  back  into  K.  The  com- 
pressed cotton  is  pushed  through  the  opening  0  and  falls 
into  the  vessel  A7,  where  it  remains  until  a  sufficiently  large 
quantity  for  further  manipulation  has  accumulated.  The 
pipe  S  serves  for  the  introduction  of  fresh  quantities  of  acid, 
the  latter  being  allowed  to  run  in  whenever  the  level  of  the 
fluid  falls  below  a  mark  on  the  wall  of  the  vessel  K. 

For  the  complete  protection  of  the  workmen  from  the 
vapors  evolved  by  the  nitrating  fluid,  the  entire  apparatus 
is  enclosed  in  a  case  of  glass  and  iron,  the  two  sliding  win- 
dows F  and  F  being  opened  only  when  cotton  is  to  be  in- 
troduced, or  taken  out.  The  gases  escape  through  the  pipe 
L,  passing  into  a  chimney  in  which  a  gas  flame  is  constantly 
burning  so  that  the  escaping  products  of  decomposition  of 
the  nitric  acid  are  completely  burnt  and  cannot  inconveni- 
ence the  neighborhood.  To  preserve  the  iron  parts  of  the 
case  from  destruction  by  the  vapors,  they  are  repeatedly 
painted  with  hot  coal  tar,  care  being  taken  to  allow  one  coat 
to  become  thoroughly  dry  before  applying  the  next  one.  If 
the  coats  are  carefully  applied  and  by  retouching  places 
which  in  the  course  of  time  show  rust  spots,  the  iron  is  per- 
fectly protected. 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).          181 

In  carrying  on  the  operation  of  nitration,  the  nitrating 
vessel  is  first  filled  with  the  appropriate  quantity  of  acid 
mixture  which  should  be  of  the  same  temperature  as  that 
usually  prevailing  in  the  factory.  The  cotton,  which 
should  be  perfectly  dry,  is  then  immersed  in  the  fluid  and 
pressed  down  to  accelerate  the  escape  of  air. 

The  proportion  between  acid  and  cotton  by  weight  may 
vary  very  much,  but  the  nitrating  vessel  must  contain  a 
sufficient  quantity  of  fluid  to  allow  of  the  cotton  being  rap- 
idly submerged  so  that  it  can  quickly  absorb  the  fluid. 

But  a  very  short  time  is  actually  required  for  nitration,  a 
piece  of  fine  tissue-paper,  for  instance,  becoming  completely 
nitrated  by  immersing  it  for  a  few  seconds  only,  in  a  mix- 
ture of  nitric  and  sulphuric  acids,  and  then  rapidly  washing 
it.  It  being,  however,  impossible  uniformly  to  moisten  in 
a  short  time  a  larger  quantity  of  cotton,  and  no  disadvan- 
tage being  connected  with  the  finished  gun-cotton  remain- 
ing somewhat  longer  in  the  acid  mixture,  no  general  rule 
regarding  the  time  the  cotton  is  to  stay  in  the  fluid  can  be 
given,  every  factory  fixing  this  point  for  itself.  When  the 
cotton  has  remained  for  the  prescribed  time  in  the  nitrating 
vessel,  it  is  taken  out,  pressed,  or  allowed  to  drain  off,  and 
is  then  thrown  into  a  vessel  for  Ihe  so-called  after-nitration, 
which  is,  however,  a  misnomer,  there  being  no  after-effect 
of  the  nitrating  fluid.  It  can  only  be  supposed  that  the 
acid  still  remaining  in  the  pores  of  the  gun-cotton  acts  upon 
the  portions  of  cellulose  which  have  escaped  its  effects  while 
in  the  nitrating  fluid,  and  converts  them  also  into  gun- 
cotton. 

In  place  of  employing  the  kind  of  vessels  above  described, 
nitration  may  also  be  effected  in  a  centrifugal  apparatus 
and  the  nitrated  cotton  dried  by  centrifugal  force.  The 
nitrating  drum  in  this  apparatus  is  usually  constructed  of 
wrought  iron  or  steel,  but  these  materials  being  subject  to 
quite  rapid  wear,  drums  of  aluminium  have  recently  been 
introduced  in  some  factories,  it  being  claimed  that  this 


182  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

metal  is  capable  of  offering  great  resistance  to  the  nitrating 
fluid. 

The  perforated  drum  of  the  centrifugal  is  enclosed  in  a 
cast-iron  jacket,  and  is  impelled  from  below.  During  the 
operation  it  is  closed,  the  vapors  evolved  being  carried  off 
by  a  pipe  in  the  lid.  The  centrifugal  is  filled  four-fifths 
full  with  acid  mixture  and,  while  slowly  revolving  the  cot 
ton  is  rapidly  introduced,  and  the  acid  is  for  about  thirty 
minutes  allowed  to  act  upon  it.  The  acid  is  then  allowed 
to  run  off,  and  the  centrifugal  is  made  to  revolve  very  rap- 
idly so  that  the  fluid  adhering  to  the  gun-cotton  is  whirled 
out,  this  operation  being  finished  in  a  short  time.  The 
drum  is  then  quickly  stopped  by  means  of  a  brake,  and  the 
gun-cotton,  which  now  feels  almost  dry,  is  lifted  out.  The 
drum  can  then  be  immediately  used  for  another  operation. 

With  the  use  of  a  nitrating  centrifugal,  so-called  after- 
nitration  is  entirely  dispensed  with,  and  care  must  be  taken 
that  by  the  employment  of  a  larger  quantity  of  nitrating 
fluid,  conversion  of  the  cellulose  into  nitro-cellulose  is  com- 
pleted in  the  centrifugal,  this  being  attained  by  taking  a 
comparatively  very  large  quantity  of  the  acid  mixture  for 
a  fixed  weight  of  cotton.  In  some  factories  a  quantity  of 
acid  mixture  amounting  to  two  hundred  times  the  weight 
of  cotton  is  used. 

Although  nitration  is  rapidly  effected  in  the  centrifugal 
apparatus,  its  use  is  not  free  from  danger,  it  having  been 
observed  that  the  cotton  frequently  ignites,  this  taking 
place  generally  towards  the  end  of  whirling  out.  This 
phenomenon  may  be  explained  by  the  rise  in  temperature 
in  the  cotton  when  pressed  with  great  force  against  the 
circumference  of  the  drum  by  the  rapid  revolution  of  the 
centrifugal. 

When  working  with  the  ordinary  apparatus,  and  then 
leaving  the  gun-cotton  to  after-nitration,  the  operation  in 
the  various  factories  takes  from  three  to  twenty-four  hours. 
It  is  advisable  to  furnish  the  vessels  used  for  after-nitration 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).          183 

with  perforated  bottoms  through  which  the  acid  draining 
off  from  the  mass  can  run  off. 


WASHING    THE    GUN-COTTON. 

In  the  further  manipulation  of  the  gun-cotton,  the  fluid 
contained  in  its  interior  has  to  be  removed,  and  replaced 
by  pure  water.  Although  this  operation  has  the  appear- 
ance of  being  very  simple,  it  nevertheless  requires  close 
attention,  since  on  the  complete  removal  of  the  fluid  depends 
not  only  the  stability  of  the  product,  but  also  security  in 
handling  and  storing  it.  It  happens  sometimes  that  in 
washing  gun-cotton  it  ignites  when  introduced  into  the 
washing  tank,  and  to  reduce  this  danger  to  a  minimum, 
the  rooms  in  which  nitration  and  after-nitration  are  effected 
should  be  entirely  separated  from  the  wash-room.  The 
vessels  used  for  after-nitration  are  placed  alongside  the  par- 
tition wall  through  which  holes  have  been  cut.  In  the 
wash-room,  underneath  these  holes,  is  an  inclined  table 
covered  with  lead.  While  one  workman  lifts  by  means  of  a 
pair  of  tongs  the  moist  hanks  from  the  vessels  and  passes 
them  through  one  of  the  holes  in  the  wall,  another  workman 
draws  them  from  the  table  and  places  them  immediately 
in  the  wash-tank. 

The  wash-tank  consists  best  of  a  trough  divided  in  the 
centre  by  a  board,  which,  however,  should  not  extend  to 
the  ends  of  the  trough.  The  wash-water  flows  in  from  the 
bottom  at  one  end  and  runs  off  through  a  notch  cut  in  the 
upper  edge  of  the  trough.  By  this  arrangement,  the  water, 
together  with  the  hanks  placed  in  it,  constantly  circulates 
in  the  trough,  all  parts  of  the  gun-cotton  being  thus  brought 
into  intimate  contact  with  it.  For  the  purpose  of  catching 
small  particles  of  gun-cotton  carried  along  by  the  water 
running  off,  a  basket  is  placed  underneath  the  notch  in  the 
trough. 

The  gun-cotton  remains  in  the  wash-tank  until,  when 
rubbed  with  litmus-paper,  the  latter  no  longer  reddens. 


184  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

It  is  then  completely  freed  from  water  by  whirling  in  a 
centrifugal. 

If  gun-cotton,  no  matter  how  carefully  washed,  be  left  for 
some  time  to  itself,  it  undergoes  changes  by  the  acid  still 
remaining  in  the  interior  of  the  cells  exerting  a  decompos- 
ing effect.  This  acid  has,  therefore,  to  be  removed,  which 
is  generally  accomplished  by  boiling  or  steaming.  Boiling 
is  effected  in  a  large  vat  with  a  false  perforated  bottom. 
The  vat  having  been  filled  with  gun-cotton  and  water, 
steam  is  introduced  below  the  perforated  bottom.  In  some 
factories  boiling  is  finished  in  three  hours,  while  in  others 
it  is  continued  for  up  to  three  days. 

In  order  to  ensure  the  removal  of  the  acid  the  water  may 
be  mixed  with  ammonium  carbonate,  about  j  to  1  oz.  per 
quart  of  water.  Steaming  after  boiling  has  been  highly 
recommended  for  obtaining  a  product  absolutely  free  from 
acid.  For  this  purpose  the  water  is  discharged  from  the 
boiling  vat,  and  steam  introduced  below  the  false  bottom 
until  it  commences  to  escape  in  a  non-condensed  state  from 
the  top.  It  is  claimed  to  have  been  observed  that  by  long- 
continued  boiling  the  content  of  nitrogen  in  the  gun-cotton 
is  decreased,  which,  of  course,  must  be  an  injury  to  it,  and 
that  this  is  not  the  case  in  continued  steaming. 

However,  by  all  these  operations  the  gun-cotton  has  not 
been  freed  from  the  last  traces  of  acid,  and  this  purpose  can 
only  be  attained  by  thoroughly  comminuting  it  in  the  pres- 
ence of  a  large  quantity  of  water.  For  masses  of  the  fibrous 
nature  of  cotton  the  best  apparatus  is  that  known  as  a  beater 
or  hollander  used  in  paper  mills  for  working  pulp.  It  con- 
sists of  an  oblong  tank  closed  on  both  ends  by  semi-circular 
pieces.  It  is  divided  by  a  short,  vertical  partition  into  two 
parts.  The  floor  of  one  part  is  sloped  and  a  box  of  knives 
is  fixed  into  it.  Over  this  box  of  knives  revolves  a  cylinder 
also  furnished  with  knives,  and  its  distance  from  the  lower 
knives  can  be  regulated  at  will.  By  the  revolution  of  the 
cylinder  the  water,  with  which  the  apparatus  is  filled,  is 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).          185 

constantly  kept  in  a  circling  motion  and  the  hanks  of  gun- 
cotton  thrown  into  the  water  are  drawn  between  the  knives 
of  the  revolving  cylinder  and  those  fixed  in  the  box,  and 
cut  up.  As  comminution  progresses,  the  cutting  cylinder 
is  lowered  until  the  distance  between  the  knives  has  finally 
been  reduced  to  fractions  of  a  millimeter. 

A  certain  portion  of  the  gun-cotton  is  for  4  to  8  hours 
treated  in  the  hollander,  or  till  the  pulp — as  the  commi- 
nuted mass  is  called — has  acquired  the  requisite  degree  of 
fineness.  It  is  then  tested  by  taking  a  sample  by  means  of 
a  ladle  from  the  trough  of  the  hollander,  and  allowing  it  to 
stand  quietly  for  some  time.  The  water  is  then  carefully 
poured  off  as  long  as  it  is  quite  clear.  Fresh  water  is  then 
poured  upon  the  sample  and  after  slightly  agitating  the 
vessel,  the  water  is  again  allowed  to  run  off.  After  this  wash- 
ing operation,  nothing  should  finally  remain  in  the  vessel ; 
if  there  should  be  a  residue  of  plainly-perceptible,  coarser 
fibres,  it  is  proof  of  the  manipulation  of  the  mass  not  hav- 
ing been  for  a  sufficiently  long  time  continued.  When  the 
mass  in  the  hollander  has  acquired  the  proper  degree  of 
fineness,  it  is  discharged  either  by  opening  a  valve  in  the 
bottom  of  the  trough,  or  by  sucking  off  with  a  pump.  The 
separation  of  the  comminuted  gun-cotton  from  the  water  is 
generally  effected  by  means  of  a  centrifugal,  the  basket  of 
which  consists  of  closely-woven  wire  lined  inside  with  linen 
cloths.  Some  fine  particles  of  gun-cotton  being  neverthe- 
less carried  along  with  the  water,  the  latter  is  first  allowed 
to  run  into  a  larger  vessel,  in  which  the  particles  of  gun- 
cotton  gradually  settle  on  the  bottom.  The  supernatant 
water  is  then  carefully  drawn  off. 

By  treatment  in  the  centrifugal  the  content  of  water  in 
the  gun-cotton  is  reduced  to  about  30  per  cent.  It  is 
brought  into  lead-lined  wooden  boxes  and  covered  with  a 
linen  cloth,  which  keeps  out  the  dust,  but  does  not  prevent 
the  mass  from  drying  slowly. 

Up  to  the  time  the  gun-cotton  is  brought  into  the  store- 


186  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

boxes  the  operations  are  the  same,  no  matter  whether  an 
explosive  product — actual  gun-cotton — or  a  readily  soluble 
product — collodion-cotton — is  to  be  prepared.  For  both 
purposes,  cotton  perfectly  free  from  water  must  be  used. 

DRYING   THE    GUN-COTTON. 

Although  gun-cotton  can  be  heated  to  between  140°  and 
158°  F.  without  igniting,  no  factory  would  dare  to  run  the 
risk  of  drying  larger  quantities  of  it  at  such  a  high  tem- 
perature, since  its  explosion  might  have  frightful  conse- 
quences. Drying  even  at  temperatures  below  122°  F.  is 
dangerous,  dry  gun-cotton  being  a  body  which  becomes 
highly  electric  by  slight  friction,  and  by  a  stronger  current 
of  air  passing  over  it  enough  electricity  might  be  generated 
for  a  spark  to  leap  over  and  ignite  the  entire  mass.  It  is, 
therefore,  necessary  to  use  special  precautions  in  drying 
gun-cotton. 

Drying  upon  frames  covered  with  linen  upon  which  the 
gun-cotton  is  spread  out  in  thin  layers,  has  the  appearance 
of  being  a  very  simple  process,  but,  according  to  Guttmann, 
it  is  objectionable,  because  the  gun-cotton  is  thereby  com- 
pletely insulated,  and  there  is  danger  of  an  electric  discharge, 
especially  if  drying  is  effected  at  a  higher  temperature. 

To  be  entirely  secure  from  an  electric  tension,  Guttmann 
uses  for  drying,  copper-plates  provided  with  conical  open- 
ings with  a  diameter  of  J  millimeter  on  top  and  of  1  milli- 
meter on  the  bottom,  thus  rendering  it  impossible  for  them 
to  be  stopped-up  by  the  gun-cotton.  The  copper  plates  are 
covered  on  the  edges  with  leather  to  prevent  friction,  and 
are  placed  one  above  the  other  in  the  drying  room.  The}- 
are  connected  one  with  the  other  by  metallic  strips,  these 
conductors  being  continued  into  the  ground.  This  arrange- 
ment renders  an  accumulation  of  electricity  in  the  gun- 
cotton  impossible,  any  electricity  developed  being  directly 
conducted  into  the  ground. 

Heating  the  drying  room  is  effected  by  air  being  con- 


NITRO— CELLULOSE    (GUN-COTTON,  PYROXYLIN).          187 

stantly  conducted  by  a  ventilator  over  a  system  of  rib- 
heating  enclosed  in  a  box.  The  air  thus  heated  passes 
beneath  the  drying  plates,  which  are  enclosed  in  boxes,  and 
leaves  them  heavily  loaded  with  moisture.  To  prevent 
heating  above  a  fixed  temperature,  the  drying  boxes  are 
furnished  with  electric  thermometers  which  indicate  by  ring- 
ing a  bell  when  the  maximum  temperature — which  should 
not  be  above  104°  F. — is  exceeded. 

Perfectly  dry  gun-cotton — and  this  applies  also  to  col- 
lodion-cotton— is  an  exceedingly  hygroscopic  body,  and 
very  rapidly  absorbs  moisture  from  the  air.  It  must, 
therefore,  when  taken  from  the  drying  boxes,  be  immedi- 
ately packed  in  air-tight  vessels,  bags  of  rubber  or  of  fabrics 
impregnated  with  rubber  being  used  for  the  purpose.  Well- 
made  wooden  boxes,  the  lids  of  which  are  made  air-tight 
by  rubber  strips  on  the  edges,  may  also  be  employed.  If 
collodion-cotton  has  been  prepared,  it  is  advisable  to  dis- 
solve it  immediately  when  it  comes  from  the  drying  boxes, 
this  having  the  additional  advantage  of  the  solutions,  by 
standing  for  some  time,  becoming  perfectly  clear. 

EXPLOSIVE   GUN-COTTON. 

The  effect  of  highly  explosive  nitro-cellulose — the  actual 
gun-cotton — intended  for  blasting  purposes,  will  be  the 
more  powerful  the  smaller  the  volume  into  which  it  is  com- 
pressed. It  is,  therefore,  made  into  cylindrical  or  prismatic 
bodies  of  known  weight,  and  the  dynamic  effect  of  such  a 
block  can  at  the  outset  be  established.  Gun-cotton  can 
only  be  pressed  while  in  a  moist  state,  and  even  when  sub- 
jected to  the  most  powerful  pressure  always  contains  a  cer- 
tain amount  of  water.  Its  explosive  power  is,  however,  not 
affected  by  this  content  of  moisture,  explosion  being  brought 
'  about  by  making,  while  pressing  the  block,  a  cj'lindrical 
opening  in  it  in  which  a  fuse  of  dry  gun-cotton  is  inserted. 

When  gun-cotton  is  to  be  compressed,  it  is  stirred  with 
luke-warm  water  to  a  thin  paste,  and  in  doing  this,  the  pro- 


188  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

portion  of  weight  of  gun-cotton  to  that  of  water  has  to  be 
known.  This  paste  is,  as  a  rule,  first  freed  from  the  larger 
portion  of  water  by  hand-presses,  the  shape  the  finished 
piece  is  to  have  being  also  given  to  it. 

The  article  thus  preparatively  pressed  is  subjected  in 
hydraulic  presses  to  as  strong  a  pressure  as  can  be  pro- 
duced. The  presses  must  be  so  arranged  that  the  water 
pressed  out  from  the  mass  can  escape,  otherwise  pressure 
would  be  ineffective,  since  fluids  oppose  great  resistance  to 
compression.  In  the  presses  variously  shaped  bodies  of 
gun-cotton  are  produced,  the  most  common  shapes  being 
cylinders  or  slightly  conical  pieces,  because  they  can  be  most 
readily  removed  from  the  moulds  of  bronze.  For  certain 
purposes,  for  instance,  for  loading  torpedoes,  the  gun-cotton 
is  compressed  in  the  form  of  cylindrical  segments,  which, 
when  put  together,  make  up  a  slightly  tapering  cylinder. 
Smaller  pieces  similar  to  the  first  ones  are  laid  one  above 
the  other,  a  body  fitting  accurately  into  the  charging  space 
of  the  torpedo  being  thus  formed.  Compressed  gun-cotton 
being  very  hygroscopic,  the  compressed  articles,  when  fin- 
ished, are  immediately  coated  with  a  water-proof  lacquer. 

INCREASING    THE    STABILITY    OF    THE    NITRO-CELLULOSE. 

The  nitro-celluloses,  so  far  as  at  present  known,  belong  to 
the  constant  combinations,  i.  e.,  they  remain  entirely  un- 
changed in  the  air  or  under  water,  a  change  taking  place 
only  in  consequence  of  an  exterior  influence.  This  im- 
mutability, however,  belongs  only  to  products  absolutely 
free  from  the  slightest  trace  of  free  acid,  nitro-celluloses 
which  contain  free  acid,  be  it  never  so  little,  being  subject  to 
change,  though  it  may  progress  very  slowly.  The  change 
manifests  itself  first  by  the  originally  pure-white  mass  turn- 
ing yellowish  and  acquiring  in  the  course  of  time  a  quite 
dark-brown  color,  and  after  a  long  time,  the  nitro-cellulose 
is  even  converted  into  a  dark-colored,  smeary  mass.  The 
author  of  this  work  noticed,  in  the  course  of  thirty  years, 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).  189 

these  phenomena  in  a  small  quantity  of  explosive  nitro- 
cellulose prepared  by  himself  and  which  was  kept  in  a 
vessel  closed  with  a  ground-glass  stopper.  Strange  to  say, 
on  opening  the  vessel,  the  mass  showed  no  odor  of  nitric 
oxide,  and  it  remained  perfectly  odorless  until  it  passed  into 
the  smeary  state.  The  gun-cotton  above-mentioned  having 
only  been  thoroughly  washed  with  cold  water  contained 
probably  small  quantities  of  free  acid. 

According  to  the  process  of  A.  Luck  and  C.  F.  Gross,  the 
stability  of  nitro-cellulose  may  be  increased  by  treatment 
with  metallic  salts,  their  solutions  being  allowed  to  act 
either  directly  upon  the  nitro-cellulose,  or  with  the  co- 
operation of  acetone.  In  the  first  case,  the  nitro-cellulose 
is  for  30  to  60  minutes  treated  in  a  one  per  cent,  solution 
of  lead  acetate  or  zinc  acetate  at  a  temperature  of  from 
176°  to  212°  F.  The  nitro-cellulose  is  then  washed  until 
the  wash  water  shows  no  trace  of  the  metallic  salt. 

According  to  the  other  process,  acetone,  to  which  has  been 
added  1  per  cent,  of  its  weight  of  the  metallic  salt,  is  poured 
over  the  nitro-cellulose,  the  treatment  being,  in  this  case, 
for  half  an  hour  at  the  ordinary  temperature.  The  fluid  is 
finally  drawn  off,  and  the  nitro-cellulose  thoroughly  washed. 
By  both  these  methods  of  treatment,  a  basic  salt  is  claimed 
to  be  formed  from  the  residue  of  acid  in  the  nitro-cellulose 
with  the  metal,  thus,  for  instance,  of  the  lead  salt  up  to  2 
per  cent,  of  lead  oxide  being  found  in  the  form  of  a  basic 
combination. 

According  to  0.  R.  Schulz's  process  the  nitro-cellulose  is 
rendered  very  stable  by  bringing  it,  when  freed  from  acid 
in  the  ordinary  manner  by  washing,  into  a  pressure-boiler, 
together  with  several  times  its  weight  of  water,  and  heating 
to  275°  F.  By  increasing  the  pressure  up  to  5  or  6  atmos- 
pheres the  operation  is  in  a  short  time  finished,  and  the 
nitro-cellulose  breaks  up  to  a  fine  powder,  in  which  form  it 
is  especially  suitable  for  the  manufacture  of  cartridges.  If 
heating  be  effected  at  as  low  a  pressure  as  3  atmospheres — 


190  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

corresponding  to  275°  F. — the  nitro-cellulose  is  also  ren- 
dered stable,  but  heating  has  to  be  continued  for  a  longer 
time. 

The  mtro-cellulose  thus  treated  in  the  boiler  is  finally 
washed  in  cold  water  for  the  removal  of  the  soluble  bodies. 
With  the  use  of  this  process  only  -fa  to  fa  of  the  quantity  of 
water  necessary  for  washing  by  the  ordinary  method  is  said 
to  be  required. 

SOLUBLE    GUN-COTTON    OR    COLLODION-COTTON. 

• 

In  describing  the  preparation  of  nitrated  cotton,  atten- 
tion has  been  drawn  to  the  fact  that  there  is  no  fixed 
boundary  between  explosive  and  soluble  gun-cotton,  but 
that  the  latter  can  be  obtained  by  a  suitable  change  in  the 
proportions  of  the  acid  mixture.  Experience  has  shown 
that  this  can  be  best  accomplished  by  using  equal  parts  of 
sulphuric  and  nitric  acids  as  nitrating  fluid.  The  nitric 
acid  should  contain  75  per  cent,  of  nitric  anhydride,  and 
the  sulphuric  acid  90  per  cent,  of  sulphuric  anhydride. 
The  fluid  is  allowed  to  act  upon  the  cotton  for  from  60  to 
90  minutes  at  a  temperature  of  104°  F.,  and  the  resulting 
product  is  immediately  washed. 

Collodion-cotton  having  recently  become  of  great  import- 
ance for  the  preparation  of  textile  threads,  to  which  the 
term  artificial  silk  has  been  applied,  greater  demands  are 
now  made  on  it  than  formerly,  when  it  was  chiefly  used 
for  photographic  and  medicinal  purposes.  For  these  appli- 
cations it  sufficed  for  the  collodion-cotton  to  dissolve  clear, 
and,  after  the  evaporation  of  the  solvent,  yield  a  film  pos- 
sessing a  certain  strength  and  elasticity. 

With  reference  to  the  use  of  collodion-cotton  for  the  manu- 
facture of  textile  threads  of  very  slight  diameter,  great  value 
is  at  present  attached  to  the  preparation  of  a  product  yield- 
ing a  solution  of  great  viscosity,  the  manufacture  of  very 
thin  threads  being  only  possible  with  such  a  solution. 

It  has  been  found  that  the  duration  of  the  action  of  the 


NITRO— CELLULOSE    (GUN-COTTON,  PYROXYLIN).  191 

acid  mixture  upon  the  cotton  exerts  great  influence  upon 
the  viscosity  of  solutions  of  collodion-cotton.  The  content 
of  nitrogen  is  also  said  to  be  of  considerable  importance, 
though  this  is  disputed  by  many  investigators. 

It  may  here  be  emphasized  that  collodion-cotton  is  never 
entirely  uniform  as  regards  its  composition,  and  that  a  pro- 
duct of  quite  uniform  general  properties  can  only  be  obtained 
by  always  working  with  cotton  of  the  same  degree  of  fineness, 
using  an  acid  mixture  of  the  same  composition,  and  con- 
ducting the  operation  in  the  same  manner  as  regards  tem- 
perature and  duration  of  the  action  of  the  acid  mixture. 
All  these  conditions  have,  therefore,  to  be  taken  into  con- 
sideration in  the  manufacture  of  large  quantities  of  collo- 
dion-cotton of  uniform  quality.  The  manufacturers  who 
require  collodion-cotton  have  determined  the  correct  pro- 
portions suitable  for  their  purposes  by  exhaustive  experi- 
ments, and  if  they  treat  their  processes  of  nitration  as 
secrets,  they  cannot  be  charged  with  assuming  an  air  of 
mysteriousness. 

For  the  production  of  collodion-cotton,  the  solutions  of 
which  are  to  possess  a  great  degree  of  viscosity,  a  higher 
temperature  should  never  be  used  for  nitration,  and  to  pre- 
vent a  rise  in  the  temperature,  it  is  advisable  to  place  the 
nitrating  vessels  in  a  tank  filled  with  cold  water.  The  pro- 
cess of  nitration  progressing  more  slowly  at  a  lower  tem- 
perature, the  cotton  is  allowed  to  remain  a  somewhat  longer 
time  in  the  acid  mixture.  It  is  then  pressed  and  imme- 
diately washed,  the  same  care  being  exercised  as  in  washing 
explosive  cotton.  The  object  of  comminuting  the  cotton  in 
the  hollander  is,  in  this  case,  not  only  to  remove  the  acids, 
but  also  to  obtain  the  product  in  a  very  finely  divided  state, 
it  being  thus  more  readily  brought  into  solution. 

According  to  the  investigations  of  G.  Lunge  and  J.  Bebie, 
previously  referred  to,  the  solubility  of  mtro-celluloses  is 
intimately  connected  with  the  content  of  nitrogen  in  the 
products  ;  gun-cotton,  which  contains  as  much  nitrogen  as 


192  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

possible,  behaving  differently  towards  various  solvents.  It 
dissolves  in  acetic  ether,  acetone,  benzol  and  nitrobenzol, 
but  not  in  nitroglycerine.  It  is,  however,  dissolved  by  a 
mixture  of  nitroglycerine  and  acetone,  such  a  solution  serv- 
ing for  the  preparation  of  one  of  the  most  effective  blasting 
agents  which  is  known  under  the  name  of  blasting-gelatine. 

Complete  solubility  in  a  mixture  of  two  parts  of  ether 
and  one  part  of  alcohol  may  be  considered  characteristic  of 
properly  prepared  collodion-cotton,  though  there  is  a  pro- 
duct which  also  dissolves  in  a  mixture  of  ether  and  alcohol 
in  which  the  proportion  of  the  latter  is' much  larger. 

If  mtro-cellulose  be  treated  at  a  moderate  heat  with 
alcoholic  solution  of  caustic  soda  or  caustic  potash,  the 
nitro-combination  is  in  a  very  short  time  disintegrated, 
cellulose  remaining  behind.  This  reaction  is  of  great 
importance  for  the  production  of  threads  and  tissues  from 
collodion  solutions,  as  by  reason  of  their  great  inflamma- 
bility they  would  be  of  no  use  whatever.  However,  when 
treated  for  a  short  time  with  solution  of  an  alkali,  they 
rank,  as  regards  inflammability,  with  ordinary  cotton  tissue. 

It  has  from  many  sides  been  asserted  that  a  good  quality 
of  collodion-cotton  can  only  be  obtained  by  nitrating  fine 
tissue-paper  which  consists  almost  entirely  of  pure  cellulose. 
Direct  experiments  in  this  direction  have  proved  that  an 
excellent  quality  of  collodion-cotton  can  actually  be  pre- 
pared from  such  paper,  it  being  only  necessary  for  the 
purpose  of  nitration,  slowly  to  draw  strips  of  the  paper  over 
glass  rods  placed  horizontally  in  the  nitrating  vessel  and 
allow  them  to  drain  off.  If,  however,  the  expense  of  pre- 
paring collodion-cotton  from  paper  is  compared  with  the 
-cost  of  producing  it  from  cotton,  the  calculation  results  in 
favor  of  cotton.  It  may  be  confidently  asserted  that  all 
that  is  necessary  is  to  free  cotton  from  all  foreign  bodies, 
•i.  e.,  to  convert  it  into  pure  cellulose,  to  be  enabled  to  pro- 
duce from  it  as  good  a  quality  of  collodion-cotton  as  from 
paper. 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).  193 

COLLODION. 

Nitrocellulose,  with  a  certain  content  of  nitrogen,  is 
capable  of  dissolving  in  a  number  of  fluids,  and  it  then  forms 
a  viscous  mass  possessing  great  adhesive  power,  to  which 
the  term  collodion  has  been  applied.  When  collodion  is 
left  to  itself  until  the  solvent  evaporates,  the  nitro-cellulose 
remains  behind  in  the  form  of  a  structureless  film,  which  is 
perfectly  colorless,  and  is  distinguished  by  considerable 
solidity  and  high  lustre. 

Collodion  found  originally  only  limited  application  in 
the  healing  art,  it  being  used  for  the  purpose  of  closing 
wounds  air-tight  to  prevent  the  colonization  of  organisms 
which  cause  gangrenous  and  other  complications  detri- 
mental to  the  healing  process. 

Solutions  of  nitro-cellulose  gained  in  importance  only 
from  the  time  when  the  use  of  collodion  in  photography 
became  general,  and  they  retained  this  importance  until 
the  photographic  process  turned  more  and  more  towards 
the  so-called  dry  plates,  the  sensitized  layer  of  which  con- 
sists of  gelatine.  However,  collodion  regained  its  great 
importance  by  reason  of  the  invention  of  the  preparation  of 
artificial  silk,  large  quantities  of  it  being  at  present  manu- 
factured for  this  purpose. 

In  speaking  later  on  of  the  manufacture  of  artificial  silk, 
the  preparation  of  collodion  for  this  purpose  will  be  referred 
to,  and  only  the  varieties  which  are  of  importance  for 
photographic  purposes  will  here  be  discussed. 

COLLODION    FOR    PHOTOGRAPHIC    PURPOSES. 

It  has  been  found  by  special  investigations  that  a  not 
highly  nitrated  nitro-cellulose  is  best  adapted  for  the  pre- 
paration of  collodion  for  photographic  purposes  as  it  dis- 
solves with  the  greatest  ease.  Several  authors  recommend 
the  finest  quality  of  tissue-paper  as  raw  material  for  its 
preparation,  but  the  same  result  is  without  question  ob- 
13 


194  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

tained  by  using,  in  place  of  this  expensive  material,  a  fine 
quality  of  purified  cotton. 

A  series  of  nitro-celluloses  is  known,  the  formation  of  which 
depends  on  the  action  for  a  varying  time  of  the  nitrating 
fluid  and,  partially,  also  on  its  concentration.  According 
to  Eber  the  composition  of  these  combinations  is  as  follows 
(the  formula  for  the  cellulose  having  been  taken  double): 

Content  of 
nitrogen. 

1.  Cellulose-hexanitrate,  C12H14O4(NO3)6  .  .    .    .  14.14  per  cent. 

2.  Cellulcse-pentanitrate,  C12H,5O5(NO3)5    .    .    .  12.75       " 

3.  Cellulose-tetranitrate,  C12H16O6(NO3)4  .  .    .    .11.11       " 

4.  Cellulose-trinitrate,  G12H17O7(NO3)3 9.15       " 

5.  Cellulose-dinitrate,  C12H18O8(NO3)2 .'  ....    6.76       " 

The  cellulose  hexanitrate  is  the  insoluble  explosive  com- 
pound which,  however,  contains  always  small  quantities  of 
soluble  substance.  Cellulose  pentanitrate  is  soluble  in  a 
mixture  of  alcohol  and  ether.  It  is  obtained  by  leaving 
cotton  for  several  hours  (up  to  five)  at  the  ordinary  tempera- 
ture in  contact  with  a  mixture  of  equal  parts  of  concen- 
trated sulphuric  and  nitric  acids  of  specific  gravity  1.40. 
The  resulting  cellulose,  as  mentioned  above,  is  soluble  in  a 
mixture  of  alcohol  and  ether,  but  if  the  mixture  contains 
only  a  small  quantity  of  ether,  the  cellulose  pentanitrate 
alone  is  dissolved,  the  admixed  tetranitrate  and  trinitrate 
remaining  undissolved. 

Cellulose  tetranitrate  may  be  obtained  by  bringing  0.63 
oz.  (18  grammes)  of  tissue  paper  cut  up  into  thin  strips, 
into  a  mixture  of  equal  parts  of  sulphuric  acid  of  specific 
gravity  1.845  and  nitric  acid  of  specific  gravity  1.40,  and 
allowing  it  to  remain  }  hour  in  the  acid  mixture,  maintain- 
ing the  temperature  during  this  time  at  176°  F.  The  pro- 
duct obtained  in  this  manner  is  identical  with  celloidin,  an 
article  furnished  by  Scheering's  factory  at  Berlin.  Besides 
tetranitrate,  trinitrate  is  also  formed,  and  the  separation  of 
the  two  compounds  is  not  readily  accomplished.  The  tetra- 


NITRO-CELLULOSE    (GUN-COTTON,  PYROXYLIN).  195 

nitrate  is  insoluble  in  ether  as  well  as  in  alcohol,  but  dis- 
solves in  a  mixture  of  them,  as  well  as  in  acetic  ether, 
methyl  alcohol,  in  a  mixture  of  acetic  ether  and  alcohol, 
and  in  glacial  acetic  acid. 

Cellulose  trinitrate  dissolves  slowly  at  the  ordinary  tem- 
perature in  absolute  alcohol ;  it  is  readily  soluble  in  acetic 
ether,  methyl  alcohol  and  boiling  glacial  acetic  acid.  A 
concentrated  alcoholic  solution  acquires  a  milky  appear- 
ance by  the  addition  of  ether. 

Cellulose  dinitrate  may  be  obtained  in  various  ways. 
According  to  one  method,  it  is  formed  by  allowing  highly 
dilute  mixtures  of  nitric  and  sulphuric  acids  to  act  at  a 
higher  temperature  upon  cellulose  until  an  abundance  of 
red  vapors  is  evolved,  and  the  mass  commences  to  dissolve. 
Dinitro-cellulose  may  also  be  obtained  by  mixing  collodion 
solution  containing  2  to  4  per  cent,  of  nitro-cellulose  with  a 
quantity  of  alcoholic  potash  lye  about  three  times  as  large 
as  would  be  required  for  the  neutralization  of  the  nitric  acid 
present.  After  one  or  two  hours,  the  fluid  is  diluted  with 
water  and  neutralized  with  dilute  sulphuric  acid,  a  floccu- 
lent  precipitate  being  formed,  which  is  carefully  washed 
and  dried.  It  consists  of  dinitro-cellulose  which  ignites 
with  difficulty  and  detonates  when  heated  to  347°  F.  It  is 
readily  soluble  in  a  mixture  of  ether  and  absolute  alcohol, 
as  well  as  in  absolute  alcohol  alone,  in  glacial  acetic  acid, 
acetic  ether,  acetone,  and  methyl  alcohol,  but  only  with 
great  difficulty  in  pure  ether. 

The  behavior  in  drying  of  a  solution  of  dinitro-cellulose 
in  ether-alcohol  is  of  special  importance  for  the  preparation 
of  collodion  for  photographic  purposes.  By  allowing  such 
a  solution  to  evaporate  upon  a  glass-plate,  a  milky-turbid, 
soft  film  is  formed  which  is  not  transparent,  but  only  trans- 
lucent. As  only  a  slight  admixture  of  this  dinitro-cellulose 
suffices  for  collodion  to  exhibit  this  phenomenon,  this  com- 
pound has  to  be  considered  as  entirely  unsuitable  for  the 
preparation  of  a  good  quality  of  collodion. 


196  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

For  the  production  of  collodion  serviceable  for  photo- 
graphic purposes  as  well  as  for  other  applications,  the 
collodion-cotton  has  to  be  perfectly  neutralized.  When  a 
sample  of  the  cotton  is  moistened  with  water,  and  after 
squeezing  out  the  water,  litmus  paper  is  reddened  by  it, 
the  acid  adhering  to  the  cotton  has  to  be  neutralized.  For 
this  purpose  the  cotton  is  for  half  an  hour  soaked  in 
ammonia  diluted  with  four  times  its  quantity  of  water, 
then  thoroughly  washed,  and  completely  dried  upon  a 
plate  placed  upon  a  pot  of  boiling  water. 

For  the  preparation  of  the  solution,  50  parts  of  ether  and 
50  parts  of  95  per  cent,  alcohol  are  used  for  2  parts  by 
weight  of  dry  cotton.  The  alcohol  is  first  poured  over  the 
cotton,  and  when  the  latter  has  swelled  up,  the  ether  is 
added,  solution  being  accelerated  by  vigorous  shaking.  A 
2  per  cent,  collodion  is  in  this  manner  obtained. 

The  physical  condition  of  collodion-cotton  has  a  notice- 
able influence  upon  its  solubility.  Pulverulent  cotton, 
which  crumbles  to  dust  when  rubbed  between  the  fingers, 
has  to  be  dissolved  in  a  mixture  of  40  parts  of  alcohol  and 
60  parts  of  ether,  otherwise  the  resulting  collodion  layer 
will  not  turn  out  solid. 

Collodion  solution  is  best  kept  in  glass  bottles  of  small 
diameter  in  a  cool,  dark  place  where  it  is  protected  from 
shocks.  After  standing  for  some  time  the  undissolved  par- 
ticles of  cotton  fall  to  the  bottom,  where  they  form  a  quite 
heavy  deposit,  the  supernatant  fluid  being  perfectly  clear. 
By  carefully  tilting  the  bottles,  the  clear  fluid  may  be 
almost  entirely  poured  off. 

The  preparation  of  collodion  solution  for  the  purpose  of 
manufacturing  artificial  silk  differs  in  many  respects  from 
the  process  above  described,  and  will  be  referred  to  in  detail 
in  speaking  later  on  of  the  manufacture  of  artificial  silk 
according  to  Chardonnet. 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  197 

ELASTIC  MASSES  FROM  NITRO-CELLULOSE  (ARTIFICIAL  RUBBER.) 

A  solution  of  nitro-cellulose  in  volatile  solvents  yields, 
after  the  evaporation  of  the  latter,  a  layer  of  structureless 
nitro-cellulose,  which,  however,  becomes  extremely  brittle 
by  drying.  This  mass  may  to  a  certain  extent  be  rendered 
more  flexible  by  adding  to  the  solution  a  small  quantity  of 
castor  oil.  The  latter  is  dissolved  in  strong  alcohol,  and  a 
quantity  of  the  solution,  amounting  to  about  2  per  cent, 
of  the  weight  of  the  dry  nitro-cellulose,  is  added  to  the 
collodion. 

The  castor  oil,  after  the  evaporation  of  the  solvent  re- 
maining, uniformly  distributed  throughout  the  nitro-cellu- 
lose, imparts  to  the  latter  a  certain  degree  of  flexibility,  and 
prevents  thin  layers  of  the  mass  from  becoming  brittle, 
without,  however,  conferring  upon  them  a  higher  degree  of 
elasticity. 

For  the  production  from  nitro-cellulose  of  masses  possess- 
ing considerable  elasticity  other  means  have  to  be  adopted. 
The  nitro-cellulose  has  to  be  dissolved  in  fluids  having  a 
high  boiling  point,  and  which  consequently  do  not  evap- 
orate in  the  air,  but  impart  to  the  mass  a  soft,  elastic 
property  similar  to  that  of  collodion  still  containing  rem- 
nants of  the  solvent. 

The  following  fluids  possess  these  properties  and  are  at 
the  same  time  capable  of  dissolving  nitro-cellulose :  Nitro- 
benzol,  uitrotoluol,  dinitrotoluol,  nitrocumol,  nitronaph- 
thalin,  etc.  However,  their  use  in  practice  is  almost  out  of 
the  question  because  they  are  too  expensive. 

A  uniform  mass  may,  to  be  sure,  be  produced  by  bringing 
dry  soluble  nitro-cellulose  in  contact  with  one  of  these  sol- 
vents or  a  mixture  of  them  ;  but  long-continued  manipula- 
tion is  required.  The  object  may,  however,  be  attained  in 
a  more  simple  manner  by  first  dissolving  the  nitro-cellulose 
in  one  of  the  volatile  solvents  ordinarily  used,  then  adding 
one  of  the  above-mentioned  less  volatile  solvents,  and  allow- 
ing the  volatile  solvent  to  evaporate. 


198  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

For  this  purpose  it  is  not  necessary  to  prepare  an  entirely 
clear  solution  of  mtro-cellulose  in  a  volatile  solvent,  only 
enough  of  the  latter  being  used  to  cause  the  nitro-cellulose 
to  swell  up  so  that  a  mass  resembling  very  thick  glue  solu- 
tion is  formed. 

A  kneading  apparatus  allowing  of  thorough  mechanical 
manipulation  is  used  for  preparing  the  mass.  Since  dur- 
ing this  manipulation,  the  volatile  solvent  would  evaporate, 
the  kneading  apparatus  should  be  placed  in  a  box  which 
can  be  closed  air-tight,  and  provision  must  be  made  for  a 
contrivance  by  means  of  which  a  current  of  warm  air  can 
be  passed  through  the  apparatus. 

The  nitro-cellulose  having  been  introduced,  the  apparatus 
is  closed,  and  the  necessary  quantity  of  solvent  admitted. 
The  most  suitable  solvent  is  a  mixture  of  equal  parts  of 
ether  and  alcohol,  though  acetone  or  methyl  alcohol  may 
also  be  used.  The  mixing  contrivance  is  then  set  in 
motion  and  kept  going  until  the  contents  of  the  apparatus 
have  been  converted  into  a  uniform  mass  in  which  no  lumps 
of  swollen,  undissolved  nitro-cellulose  are  noticed.  The 
heavy  volatile  solvent  is  then  introduced,  and  the  mixing 
apparatus  kept  constantly  in  motion  until  the  mass  has 
again  become  homogeneous.  This  is  the  period  at  which 
the  greater  part  of  the  volatile  solvent  may  be  regained  by 
distillation. 

For  this  purpose  a  current  of  warm  air  is  passed  through 
the  apparatus,  and,  when  loaded  with  the  vapors  of  alcohol 
and  ether,  is  conducted  through  a  cooling  pipe  in  which 
the  vapors  are  condensed.  However,  the  entire  quantity  of 
volatile  solvent  must  not  be  distilled  off,  otherwise  the  mass 
in  the  apparatus  would  become  so  viscous  as  to  clog  the 
kneading  contrivance. 

The  further  manipulation  of  the  mass  is  effected  by  rolls, 
the  rest  of  the  volatile  solvent  still  contained  in  it  being 
thereby  completely  evaporated.  Rolling  has  to  be  several 
times  repeated  to  make  the  mass  thoroughly  homogeneous. 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  199 

The  nature  of  the  masses  finally  obtained  depends  on  the 
proportional  quantities  of  nitro-cellulose  and  solvent.  The 
more  of  the  latter  is  present  the  more  elastic  the  masses 
will  be,  and  by  a  suitable  change  in  the  proportions,  masses 
almost  equal,  as  regards  softness  and  elasticity,  to  a  fine 
quality  of  rubber  may  be  obtained.  The  smaller  the  quan- 
tity of  solvent,  the  more  solid  and  harder  the  resulting 
masses  will  be. 

These  masses,  when  heated,  acquire  a  higher  degree  of 
stablity,  and  can  then  by  pressure  be  brought  into  any 
shape  desired,  and  as  they  can  be  readily  mixed  with  in- 
different bodies,  articles  of  very  varying  appearance  may 
be  made  of  them.  For  mixing  purposes,  powders  of  cheap, 
indifferent  bodies,  such  as  chalk,  asbestus,  talcum,  etc.,  are 
especially  suitable.  If  other  than  white  masses  are  to  be 
prepared,  any  desired  coloring  matter  may  be  mixed  with 
the  white  powders,  colored  masses  of  very  neat  appearance 
being  thus  obtained.  On  account  of  their  great  elasticity, 
the  term  artificial  rubber  has  been  applied  to  these  peculiar 
nitro-cellulose  masses,  and  for  many  purposes  they  may 
serve  as  substitutes  for  rubber. 

The  above-described  masses,  consisting  as  they  do  largely 
of  nitro-cellulose,  are  quite  inflammable,  without,  however, 
exhibiting  any  explosive  properties.  The  inflammability, 
however,  becomes  less  with  the  use  of  a  larger  quantity  of 
indifferent  substances,  it  being  thereby  actually  reduced  to 
a  very  slight  degree,  and  it  may  be  still  further  decreased 
by  superficially  denitrating  the  finished  articles.  This  is 
accomplished  by  dipping  them  for  a  short  time  in  hot  soda 
lye,  the  outer  layers  of  nitro-cellulose  being  thereby  con- 
verted into  cellulose.  An  article  thus  treated  will  not 
ignite,  even  when  brought  in  contact  with  a  red-hot  body, 
the  point  of  contact  being  simply  blackened  by  the  carbon- 
ization of  the  outer  cellulose  layers. 

The  elastic  nitro-cellulose  masses  prepared  according  to 
the  process  above  described,  are  by  many  investigators  con- 


200  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

sidered  as  deserving  the  greatest  attention  of  all  the  bodies 
which  have  been  proposed  as  substitutes  for  rubber,  they 
approaching  nearest,  as  regards  their  properties,  the  genu- 
ine article,  without,  however,  being  capable  of  entirely  re- 
placing it. 

CELLULOSE    ESTERS. 

In  addition  to  the  esters  yielded  by  cellulose  by  the 
action  of  nitric  acid,  analogous  combinations  with  other 
acids  may  be  prepared.  But  a  small  number  of  combina- 
tions belonging  to  this  series  are  at  present  known,  but  it 
may  be  supposed  that  many  of  them  may  in  the  future  ac- 
quire a  certain  importance  for  the  industries.  It  has, 
therefore,  been  considered  advisable  to  give  a  few  facts 
regarding  the  nature  and  preparation  of  these  combinations. 

CELLULOSE  ACETIC  ESTER. 

Cellulose  tetra-acetate  or  cellulose  acetic  ester  is  prepared, 
according  to  Henckel— Donnersmark's  process,  from  a  mole- 
cular mixture  of  cellulose  and  magnesium  acetate,  and, 
therefore,  630  grammes  (21.87  ozs.)  of  magnesium  acetate 
have  to  be  used  for  every  720  grammes  (25.39  ozs.)  of 
cellulose,  pure  cellulose  prepared  from  cellulose  sulpho- 
carbonate  being  said  to  be  especially  suitable  for  preparing 
the  combination.  The  above-mentioned  mixture  of  cellu- 
lose and  magnesium  acetate  is  intimately  mixed  in  a 
kneading  machine,  the  mixing  vessel  of  which  can  be 
heated,  with  810  grammes  (28.57  ozs.)  of  acetyl  chloride 
and  450  grammes  (15.87  ozs.)  of  anhydrous  acetic  acid. 
When  the  chemicals  commence  to  act  one  upon  the  other 
4.5  liter  (4.65  quarts)  of  nitrobenzol  are  added  in  very  small 
portions  at  a  time,  a  fresh  quantity  being  only  added  when 
the  previous  one  has  been  completely  taken  up  by  the  mass. 
The  addition  of  the  nitrobenzol  is  so  managed  that  about 
one-half  of  it  remains  when  the  temperature  of  the  mass 
has  risen  to  158°  F.  This  quantity  is  then  at  one  time 
brought  into  the  mixing  vessel,  and  the  mixing  machine 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  201 

kept  going  for  three  hours  longer.  A  thinly-fluid  solution 
of  the  tetra-acetate  still  containing  traces  of  unchanged 
cellulose  and  of  lower  acetates  is  thus  obtained. 

The  warm  solution  is  poured  into  22.5  liter  (23.76  quarts) 
of  alcohol,  the  acetate  precipitating  thereby  as  a  white, 
finely-flocculent  mass,  which  is  separated  from  the  fluid  by 
filtration.  This  flocculent  mass  is  washed  with  warm  alco- 
hol, the  washing  fluid  is  added  to  the  mother-lye,  and  the 
flocculent  mass  subjected  to  strong  pressure.  It  is  then, 
without  previous  drying,  comminuted,  stirred  together  with 
water,  and  boiled  in  the  latter  until  the  last  traces  of  the 
solvent  have  been  evaporated.  The  mass  is  then  again 
filtered,  washed  first  with  warm  water  acidulated  with  a 
small  quantity  of  hydrochloric  acid  to  remove  the  last 
traces  of  the  magnesium  salt,  and  then  with  pure  warm 
water,  until  the  fluid  running  off  shows  a  neutral  reaction. 
It  is  then  again  subjected  to  pressure  and  finally  dried  at 
a  temperature  not  exceeding  176°  F.  Of  the  homologues 
of  nitrobenzol,  Henckel-Donnersmark  has  used  with  equal 
success  o-nitrotoluol,  p-nitrotoluol,  o-nitro-ethylbenzol  and 
the  nitroxylols  and  nitrocumols  from  isopropyl-benzol. 

The  composition  of  cellulose  tetra-acetate  corresponds  to 
the  formula  C6H6O6(C2H30)4.  The  combination  is  in- 
soluble in  methyl  alcohol,  ethyl  alcohol,  ethyl  acetate,  amyl 
acetate,  acetones  -and  ether ;  it  dissolves  in  ethyl-benzoate, 
chloroform,  glacial  acetic  acid  and  nitrobenzol.  The  solu- 
tion in  nitrobenzol  congeals  on  cooling  to  a  solid,  perfectly 
transparent  jelly. 

When  a  solution  of  cellulose  tetra-acetate  is  poured  upon 
a  glass-plate  and  allowed  to  evaporate,  the  combination  is 
left  behind  in  the  form  of  laminae  of  extraordinary  trans- 
parency which  show  considerable  solidity  even  when  just 
of  such  a  thickness  as  still  to  exhibit  the  iridescence  of  very 
thin  layers.  Towards  the  action  of  chemicals,  the  combi- 
nation shows  a  degree  of  indifference  which  considerably 
surpasses  that  of  nitro-cellulose,  it  being  not  attacked  by 


2€2  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

alkalies,  which  produce  no  effect  whatever  even  at  a  higher 
temperature.  The  combination  is  only  destroyed  by  boil- 
ing it  for  several  hours  in  alcoholic  soda  lye,  cellulose  re- 
maining  behind  which,  however,  retains  the  form  of  laminae, 
as  well  as  the  transparency. 

One  property  of  the  combination  which  may  perhaps  be- 
come of  great  technical  importance,  is  its  insulating  power, 
which  is  better  than  that  of  rubber  or  gutta-percha.  The 
acetate  softens  only  at  about  302°  F.,  and  is  not  inflam- 
mable. 

The  great  chemical  indifference  of  this  substance  and  its 
extraordinary  insulating  power  may  secure  for  it  consider- 
able application  in  the  electrical  industry.  For  many  pur- 
poses it  might  also  serve  as  a  substitute  for  celluloid, 
especially  in  cases  where  the  use  of  this  material  is  excluded 
by  reason  of  its  great  inflammability.  Since,  as  previously 
mentioned,  very  thin,  but  nevertheless  very  solid,  laminae 
can  be  obtained  by  the  evaporation  of  dilute  solutions  of 
the  ester,  such  solutions  might  prove  very  suitable  for 
lacquering  metals  to  protect  them  from  atmospheric  action. 

According  to  L.  Lederer  an  acetyl  derivative  of  cellulose 
is  prepared  by  bringing  hydro-cellulose  in  contact  with  sul- 
phuric acid  and  acetic  anhydride  at  a  temperature,  which 
should  not  be  much  above  158°  F.,  the  process  being  as 
follows :  The  cellulose  is  allowed  for  a  few  minutes  to  re- 
main in  contact  with  dilute  (3  per  cent.)  sulphuric  acid. 
It  is  then  pressed  out,  dried  and  heated  for  three  hours  at 
158°  F.  Four  times  the  quantity  of  acetic  anhydride  is 
then  poured  over  it.  A  vigorous  disengagement  of  heat 
immediately  takes  place,  and  the  heat  in  the  interior  of  the 
closed  vessel  must  be  so  moderated  by  cooling  that  it  does 
not  exceed  158°  F.  The  hydro-cellulose  is  gradually  dis- 
solved and  when  reaction  is  complete,  the  mass  is  mixed 
with  water,  thoroughly  washed,  and  dried. 

The  acetylated  cellulose  thus  obtained  forms  a  white 
powder  of  a  gritty  nature,  soluble  in  chloroform  or  nitro- 


NITROCELLULOSE    (GUN-COTTON,  PYROXYLIN).  203 

benzol.  According  to  Lederer,  the  acetyl-cellulose  prepared 
in  the  manner  above  described,  is  especially  suitable  as  a 
substitute  for  collodion,  and  for  the  preparation  of  articles 
resembling  celluloid  in  appearance,  but  distinguished  from 
it  by  being  perfectly  free  from  odor  and  not  being  inflam- 
mable. 

Lederer  has  later  on  modified  his  process  by  submitting 
the  mass,  after  adding  the  acetic  acid,  to  uninterrupted 
mechanical  manipulation,  the  temperature,  by  constant 
cooling,  being  prevented  from  rising  above  86°  F.  The 
mechanical  manipulation  is  continued  until  the  mass  pre- 
sents the  appearance  of  transparent  paste,  when,  by  the 
addition  of  water,  the  acet3rl-cellulose  is  separated  and  fur- 
ther worked. 

CELLULOSE    BUTYRIC    ESTER. 

Cellulose  tetra-butyrate  or  cellulose  butyric  ester  is  pre- 
pared in 'a  manner  analogous  to  the  acetate,  and,  as  regards 
its  properties,  closely  resembles  the  latter,  but  is  distin- 
guished from  it  by  being  more  readily  soluble  in  the 
solvents  above-mentioned,  and  dissolving  also  in  ethyl  ace- 
tate and  in  acetone.  Laminae  obtained  from  the  butyrate 
by  allowing  solutions  of  it  to  evaporate,  are  somewhat  softer 
and  more  flexible  than  laminaB  from  the  acetate. 

In  addition  to  the  above-mentioned  esters,  Henckel- 
Donnersmark  has  prepared  a  series  of  similar  combinations, 
for  instance,  the  double  ester — cellulose  aceto-butyrate — 
further,  cellulose  palmitate,  cellulose  phenyl-acetate,  etc. 
As  regards  their  properties,  these  combinations  show  a  cer- 
tain resemblance  to  those  previously  described.  Thus  far, 
no  application  of  them  in  the  industries  has  become  known. 


A  peculiar  use  is  made  of  cellulose  acetate,  according  to 
statements  by  the  "  Farbenfabriken,"  formerly  Fr.  Boyer  & 
Co.,  for  the  purpose  of  bringing  alcohol  into  a  solid  form — 


204  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

solid  spirit  For  the  preparation  of  this  peculiar  product, 
100  grammes  (3.52  ozs.)  of  cellulose  tri-acetate  are  dissolved 
in  500  grammes  (17.63  ozs.)  of  glacial  acetic  acid  and  the 
solution  is  quickly  brought  into  2  liters  (2.113  quarts)  of 
alcohol.  Cylindrical  structures  of  a  gristly  nature  are 
formed  from  which  the  excess  of  glacial  acetic  acid  and 
alcohol  is  removed  by  pressure.  They  are  then  dried  in 
the  air  and  kept  in  closed  vessels  for  use.  When  heated 
the  product  does  not  melt,  and  when  ignited,  burns  .uni- 
formly without  leaving  a  residue. 


IX. 

ARTIFICIAL  SILK. 

THE  substance  to  which  the  general  term  silk  has  been 
applied  is  the  product  of  the  larva?  or  caterpillars  of  different 
Lepidoptera  of  the  genus  Bombyx,  and  of  a  few  other  varie- 
ties. When  the  larva  has  attained  its  period  of  full  growth, 
it  contains  in  large  vessels,  almost  occupying  its  entire 
body,  a  glutinous  fluid  which  is  either  colorless  or  yellow, 
or  sometimes  orange-red.  These  vessels  are  by  means  of 
very  small  apertures  connected  with  a  spinner  on  the  pos- 
terior of  the  larva,  and  while  the  latter  spins  its  cocoon  the 
glutinous  fluid  passes  in  unbroken  lines  through  the  aper- 
tures of  the  spinner. 

The  glutinous  fluid  immediately  coagulates  under  con- 
tact with  air  to  a  very  thin  thread,  which  is  either  colorless, 
yellow  or  orange-red,  and  represents  the  raw  silk.  How- 
ever, the  latter  does  not  consist  of  a  uniform  mass,  but  of 
two  distinct  bodies.  The  outer  layer  is  gelatinous  and 
gummy,  forming  the  so-called  silk-glue,  and  has  to  be  re- 
moved previous  to  the  further  manipulation  of  the  raw  silk. 
The  core  enclosed  by  this  outer  layer  is  the  actual  silk  sub- 
stance, or  sericin,  or  fibroin.  In  addition  to  these  substances, 
several  other  bodies,  such  as  albumen,  coloring  matter,  wax 
and  fat,  occur  in  silk.  The  composition  of  raw  silk  is, 
therefore,  quite  complex,  and  consists,  as  a  rule,  of  20  per 
cent,  of  the  gelatinous  substance  ;  53  per  cent,  of  actual  silk 
substance  or  sericin ;  24  per  cent,  of  albuminous  combina- 
tions, and  3  to  4  per  cent,  coloring  matter,  fat  and  wax. 

By  a  special  operation,  called  scouring  or  boiling,  the 
raw  silk  is  deprived  of  all  other  substances  except  the  seri- 

(205) 


206  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

cin  or  fibroin,  when  it  can  be  further  worked  by  mechani- 
cal means.  This  operation  is  generally  effected  by  repeat- 
edly boiling  the  raw  silk  with  soap  solutions. 

Viewed  under  the  microscope,  a  thread  of  silk  freed  from 
its  envelope  of  gummy  matter  appears  as  a  massive  cylinder 
(without  cavity),  resembling  in  its  appearance  a  glass  rod, 
and  showing  here  and  there  very  slight  cross-stripes.  The 
diameter  of  the  individual  threads  is  very  slight,  vary- 
ing according  to  the  degree  of  fineness  of  the  silk  between 
^V  and  ^  of  a  millimeter.  Notwithstanding  this  slight 
thickness,  silk  threads  possess  an  uncommonly  high  degree 
of  strength  and  elasticity  by  far  surpassing  in  this  respect 
all  other  textile  fibres. 

Silk  being  not  available  in  unlimited  quantities  and  the 
demand  for  it  being  constantly  on  the  increase,  chemists 
have  for  a  long  time  endeavored  to  produce  it  by  artificial 
means,  but  the  results  have  always  proved  unsatisfactory. 
However,  efforts  to  obtain  masses  for  the  production  of 
threads  which,  as  regards  fineness  and  lustre,  closely  re- 
semble actual  silk  and  can  be  spun  and  twisted,  have  been 
more  successful,  but  none  of  these  substitutes  for  silk  can, 
as  regards  strength  and  elasticity,  compare  with  the  natural 
product,  even  the  best  of  them  being  in  this  respect  far  in- 
ferior to  it. 

VARIETIES    OF    ARTIFICIAL    SILK. 

Three  varieties  of  silk-substitutes  or  artificial  silk  may  at 
present  be  distinguished  and  according  to  their  origin  may 
be  designated  as  cellulose-silk,  collodion-silk,  and  glue-  or 
gelatine-silk. 

As  the  matter  stands  at  present,  pre-eminence  above  all 
other  substitutes  has  to  be  given  to  collodion-silk,  while 
glue-silk  decidedly  occupies  the  lowest  place.  However, 
cellulose-silk  might  in  the  future  take  precedence  over 
collodion-silk,  it  possessing  decided  advantages  over  the 
latter. 


\t\\W 


ARTIFICIAL    SILK.  207 

With  reference  to  the  historical  development  of  the  artifi- 
cial silk  industry,  the  French  chemist  M.  de  Chardonnet 
was  the  first  to  occupy  himself  successfully  with  this  sub- 
ject. As  early  as  1884  he  deposited  with  the  French 
Academic  des  sciences  a  sealed  document,  which  was  opened 
November  7,  1887,  and  bore  the  title  Sur  une  mature  textile 
artificielle  resemblant  a  la  soie  (on  an  artificial  textile  sub- 
stance resembling  silk). 

The  process  for  the  production  of  a  textile  substance 
resembling  silk  suggested,  in  1889,  by  Du  Vivier,  and 
designated  by  him  as  soie  de  France,  can  only  be  considered 
a  modification  of  Chardonnet's  method.  Du  Vivier,  as  well 
as  Lehner,  uses  solutions  of  nitro-cellulose  for  the  produc- 
tion of  textile  threads,  this  being  also  the  pith  of  the  first 
invention,  collodion  being  Ohardonnet's  initial  material. 

Lehner  also  starts  off  with  nitro-cellulose,  but  employs 
for  its  solution  substances  differing  from  those  used  by 
Chardonnet,  and  mixes  this  solution  with  silk-fibroin  pre-. 
pared  from  silk  waste,  or  with  solution  of  artificial  rubber 
prepared  from  drying  oils.  The  fluid  pressed  into  the  form 
of  a  thread  is  conducted  into  a  bath  of  oil  of  turpentine,  or 
of  a  mineral  oil,  in  which  it  coagulates,  and  the  thread  thus 
obtained,  which  is  still  soft  and  viscous,  is  stretched  pre- 
vious to  being  reeled  up. 

A.  Millar  utilizes  for  the  production  of  textile  threads  the 
property  of  glue  solution  mixed  with  potassium  dichromate, 
becoming  insoluble  on  exposure  to  light.  For  this  purpose 
a  clear  solution  of  gelatine  is  mixed  with  solution  of  potas- 
sium dichromate,  the  solutions  being  prepared  in  the  pro- 
portion of  100  parts  of  gelatine  to  2  or  2J  parts  of  potassium 
dichromate.  The  fluid  should  only  contain  sufficient  water 
to  emerge  from  the  narrow  spinning  apertures  in  the  form 
of  a  viscous  thread,  which  on  exposure  to  light  becomes 
insoluble. 

Hummel,  of  Leeds,  converts  pure  gelatine  solution  into 
threads,  dries  them  and  prepares  from  16  to  18  such 


208  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

threads,  skeins,  which  are  exposed  to  the  vapors  of  formalin, 
whereby  the  gelatine  is  deprived  of  its  solubility  in  water. 

Comparative  experiments  have  shown  that  threads  pre- 
pared from  glue  (gelatine)  possess  a  comparatively  high 
degree  of  brittleness,  and  in  addition  have  the  very  dis- 
agreeable property  of  swelling  up  very  much  in  moist  air. 

Cadoret  uses  in  his  method  an  intermediary  between 
Chardonnet  and  Millar's  processes.  He  dissolves  dinitro- 
cellulose  in  a  mixture  of  ether  and  acetic  acid,  and  mixes 
this  solution  with  glue  solution  or  albuminous  substances, 
so  that  a  fluid  is  formed  which  can  be  drawn  out  to  thin 
threads.  The  latter  acquire  solidity  by  being  drawn  through 
a  tannin  solution,  by  which  the  glue  substance  or  the  albu- 
men is  transformed  into  an  insoluble  body.  The  thread 
obtained  by  this  process  consists,  therefore,  of  a  mixture  of 
dinitro-cellulose  and  the  combination  of  tannin  and  glue,  or 
albumen. 

The  methods  according  to  which  textile  threads  are  pre- 
pared from  pure  cellulose  instead  of  nitro-cellulose  differ 
essentially  from  those  mentioned  above.  Several  processes 
in  this  direction  have  become  known,  each  of  which  may, 
however,  be  considered  as  original,  though  of  greatest  im- 
portance is  perhaps  the  method  according  to  which  a  solu- 
tion of  cellulose  in  cuprammonium  is  prepared,  and  the 
cellulose  again  separated  in  the  form  of  fine  threads. 
Several  such  processes  for  the  preparation  of  textile  threads 
from  cellulose  are  known,  but  only  one  of  them  has  thus  far 
been  permanently  introduced  in  practice,  this  being  the  in- 
vention of  Dr.  Hermann  Pauly,  of  Gladbach,  which  is  at 
present  carried  on  on  a  large  scale.  A  process  in  which  the 
use  of  nitro-cellulose  is  also  avoided  has  been  proposed  by 
Langhaus.  It  consists  in  the  main,  in  kneading  cellulose 
with  sulphuric  and  phosphoric  acids  into  a  doughy  mass, 
which  is  diluted  with  sufficient  phosphoric  acid  to  form  a 
viscous  mucilage  capable  of  being  spun.  No  particulars  of 
the  availability  of  this  process  on  a  large  scale  are  known, 


ARTIFICIAL    SILK.  209 

but  it  will  very  likely  not  become  of  practical  importance, 
if  for  no  other  reason  than  that  in  cuprammonium  and  vis- 
cose we  have  materials  which  allow  of  a  more  easy  manipu- 
lation of  the  mass  than  is  the  case  when  highly  concentrated 
acids  have  to  be  used  for  its  preparation. 

By  reason  of  its  cheapness  and  safety,  an  excellent  method 
for  the  preparation  of  silk-like  threads  is  the  one  in  which 
viscose  solution  is  used,  it  being  possible,  even  at  the  pres- 
ent state  of  the  process,  to  produce  textile  threads  which,  as 
regards  beauty,  are  not  inferior  to  Chardonnet  silk.  From 
the  present  state  of  the  manufacture  of  textile  threads  by 
artificial  means,  it  would  seem  very  probable  that  Char- 
donnet's  process  can  gain  a  permanent  position  in  practice 
only  when  the  skeins  can  be  successfully  deprived  of  their 
great  inflammability.  As  regards  the  methods  in  which 
cellulose  solutions  are  worked,  the  process  in  which  cup- 
rammonium is  employed  as  solvent,  as  well  as  the  one  with 
viscose,  appears  to  have  a  great  future  before  it. 

It  may  here,  however,  be  most  emphatically  stated  that 
for  all  that,  the  services  rendered  by  Chardonnet  in  creating 
this  entirely  new  branch  of  industry  are  not  the  less  great, 
because  he  not  only  made  the  first  suggestions,  but  per- 
fected the  mechanical  part  of  the  entire  manufacture  so 
that,  in  this  respect,  the  work  of  all  inventors  after  him  has 
been  essentially  facilitated. 

CHARDONNET    ARTIFICIAL    SILK. 

According  to  Chardonnet's  original  patent,  the  process  of 
preparing  textile  threads  is  as  follows :  One  hundred 
grammes  (3.52  ozs.)  of  pyroxylin  together  with  10  grammes 
(0.35  oz.)  of  a  reducing  metallic  protochloride,  such  as 
protochloride  of  iron,  chromium,  manganese  or  tin,  and  0.2 
grammes  (3.08  grains)  of  an  oxidizable  base,  such  as,  for 
instance,  quinine,  aniline  or  rosaniline,  are  dissolved  in  a 
mixture  of  40  parts  of  ether  and  60  parts  of  alcohol,  and  a 
coloring  substance  is  added  to  the  warm  solution.  This 
14 


210  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

fluid  is  pressed  through  a  narrow  tube,  which  is  surrounded 
by  cold  water.  The  thin  thread  thus  obtained  coagulates 
immediately  on  the  surface,  while  the  interior  still  remains 
liquid.  Hence,  previous  to  complete  coagulation,  this 
thread  may  be  stretched,  and  this  is  done  so  far  as  the 
tenacity  of  the  substance  will  permit  without  tearing  the 
thread.  The  finished  thread  is  then  dried  and  reeled  up. 

Based  upon  this  method,  the  merest  outlines  of  which  are 
given  above,  several  factories  are  at  present  working  in 
France,  and  in  Switzerland,  and  one  in  England,  and  the 
establishment  of  others  is  said  to  be  in  contemplation. 

Regarding  the  practical  application  of  Chardonnet's 
process,  the  following  details  have  become  known : 

Perfectly  pure  cellulose  always  serves  as  raw  material, 
and  cellulose  of  any  derivation  may  be  used,  provided  it 
has  been  sufficiently  purified.  However,  it  has  been  shown 
by  comparative  experiments  that  the  product  obtained  from 
cellulose  prepared  from  wood  is  far  inferior  to  others  as 
regards  purity  and  beauty  of  the  white  color,  as  well  as 
tenacity.  Hence  in  factories  working  according  to  Char- 
donnet's  process,  pure  cotton  is  used  as  the  starting  point 
in  the  manufacture.  The  cotton  is  first  carefully  cleansed 
by  mechanical  means  and  then  further  chemically  purified 
by  weak  alkaline  solutions,  so  that  it  may  be  considered 
pure  cellulose.  It  is  finally  loosened  up  in  a  carding 
machine,  and  then  subjected  to  nitration. 

NITRATION    OF    THE    COTTON. 

The  nitrating  fluid  is  prepared  from  nitric  and  sulphuric 
acids,  great  importance  being  attached  to  its  being  always 
of  exactly  the  same  composition.  This  also  contributes  to 
the  nitro-cellulose  showing  at  all  times  the  same  composi- 
tion, which  is  still  further  promoted  by  constantly  executing 
all  the  operations  during  nitrating  according  to  exactly  the 
same  plan. 

Fifteen  parts  of  fuming  nitric  acid,  of  1.52  specific  gravity, 


ARTIFICIAL   SILK.  211 

and  85  parts  of  sulphuric  acid  are  used.  The  mixture  is 
prepared  in  the  morning,  and  such  care  is  exercised  that 
even  the  content  of  moisture  in  the  air  of  the  previous  night 
is  taken  into  consideration,  because  in  damp  nights  the 
sulphuric  acid  absorbs  somewhat  more  water  than  in  dry 
nights  ;  hence,  in  the  first  case,  a  somewhat  larger  quantity 
of  sulphuric  acid  has  to  be  taken.* 

Stone-ware  pots,  each  holding  about  40  quarts,  are  used 
for  nitrating  vessels,  and  8.8  Ibs.  of  dry  cotton  are  brought 
into  each  pot,  and  35  quarts  of  acid  mixture  are  imme- 
diately poured  over  them.  The  pots  are  placed  under  a 
contrivance  for  carrying  off  the  vapor  evolved.  Imme- 
diately after  the  acid  mixture  has  been  poured  over  the 
cotton,  the  contents  of  the  pot  are  thoroughly  stirred,  so 
that  all  portions  of  the  cotton  become  completely  moistened 
with  the  fluid.  The  pots  are  then  covered  with  glass  plates. 

The  time  during  which  the  cotton  remains  in  contact 
with  the  acid  depends  materially  on  the  temperature  of  the 
air.  It  is  also  stated  that  the  content  of  moisture  in  the  air 
is  also  of  influence,  but  this  appears  not  quite  clear  because 
gases  endeavoring  to  escape  outward  hang  constantly  over 
the  fluid  in  which  the  cotton  is  immersed  and,  furthermore, 
the  pots  are  covered  with  glass  plates.  If  the  content  of 
water  in  the  acid  has  been  too  large,  the  nitrated  cotton 
does  not  completely  dissolve,  and  if  the  temperature  has 
been  too  high,  a  portion  of  the  cotton  is  entirely  destro}rcd. 
To  obtain  a  thoroughly  uniform  product  it  would,  therefore, 
seem  advisable  always  to  use  an  acid  mixture  of  one  and 
the  same  temperature  and  to  place  the  nitrating  vessels  in 
a  large  holder  in  which  a  strong  current  of  cold  water  con- 
stantly circulates.  By  working  in  this  manner  there  will 
be  no  difficulty,  after  a  few  experiments,  to  determine  ac- 

*  If  the  sulphuric  acid  be  kept  in  vessels  closed  air-tight,  moist  air  exerts  no 
influence  whatever  upon  it,  and  it  would  seem  that  these  statements  are  only 
made  for  the  purpose  of  representing  to  the  public  the  manufacture  as  a  matter 
of  particular  difficulty. 


212  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

curately,  within  a  few  minutes,  the  time  required  for  nitra- 
tion. (Compare  as  regards  this  subject,  the  investigations 
of  G.  Lunge  and  J.  Bebie  previously  referred  to.) 

When  nitration  has  been  correctly  carried  on,  the  struct- 
ure of  the  cotton  shows  no  change,  it  being  only  somewhat 
coarser  to  the  feel  and  more  brittle.  The  physical  behavior 
of  the  nitrated  cotton  exhibits,  however,  a  very  essential 
change,  especially  as  regards  its  behavior  towards  polarized 
light,  which  is  closely  connected  with  the  degree  of  nitra- 
tion, though  the  latter  may  also  be  established  by  the  di- 
rect determination  of  the  nitric  oxide  formed  from  a  weighed 
quantity  of  nitro-cellulose.  However,  the  physical  exami- 
nation being  less  troublesome  and,  what  is  the  main  point 
in  this  case,  requiring  but  little  time,  the  degree  of  nitra- 
tion is  determined  with  the  assistance  of  the  polariscope. 
Chardonnet,  in  compiling  a  series  of  comparative  experi- 
ments in  the  chemical  and  optical  way,  arrived  at  the  fol- 
lowing results : 

1.  Nitration  has  progressed  to  the  formation  of  cellulose 
tetranitrate,  corresponding  to  the  development  of  110  cubic 
cm.  nitric  oxide  from  every  1  g.  of  nitrated  cotton.     At  this 
stage  nothing  striking  is  seen  in  the  polariscope  except  a 
few  large  fibres  of  a  shriveled-up  appearance. 

2.  The  polariscope  shows  the  above-mentioned  fibres  to 
be  present  in  larger  numbers  and  already  mixed  with  iri- 
descent  fibres.     The  product  yields  145  cubic  cm.  nitric 
oxide,  and  is  cellulose  hexanitrate.     From  146  cubic  cm. 
nitric  oxide  up,  the  fibres  become  more  uniformly  gray, 
this  continuing  to  160  cubic  cm. 

3.  From  160  cubic  cm.  on — cellulose  heptanitrate  being 
now  present — up  to  180  cubic  cm.,  the  color,  when  the  mass 
is  tested    in  the   polariscope,  turns  from    straw-yellow   to 
orange-red. 

4.  When  the  quantity  of  nitric  oxide  evolved  becomes 
greater  than  160  cubic  cm.,  the  mass  is  first  colorless,  then 
violet,  dark-blue  and  pale-blue,  the  latter  color  becoming 


ARTIFICIAL    SILK.  213 

the  more  pronounced  the  farther  nitration  progresses. 
When,  in  polarized  light  all  the  fibres  appear  uniformly  of 
a  pale-blue  color,  it  is  an  indication  of  nitration  being 
complete. 

The  cotton  is  then  lifted  from  the  nitrating  vessel, 
allowed  to  drain  off,  and  the  adhering  acid  removed  by 
means  of  a  hydraulic  press.  The  acid  thus  recovered  is 
mixed  with  an  adequate  quantity  of  fresh  acid  and  again 
used  for  nitration.  The  manipulation  in  the  hydraulic  press, 
of  the  nitrated  cotton,  saturated  with  acid,  creates  difficul- 
ties in  so  far  that  the  metal  parts  of  the  press  are  strongly 
attacked.  This  is  prevented  by  coating  them  with  lead, 
plates  of  the  same  material  being  also  used  for  covering  the 
floors  of  the  rooms  in  which  acid  is  handled. 

The  gun-cotton  comes  from  the  hydraulic  press  in  the 
form  of  solid  cakes,  which  are  immediately  comminuted  in 
the  hollander,  and  washed.  The  hollander  most  suitable 
for  this  purpose  is  furnished  with  a  horizontal  shaft  around 
which  stirring  paddles  revolve.  The  size  of  the  machine 
should  be  such  that  88  Ibs.  of  dry  material,  as  it  comes 
from  the  press,  can  at  one  operation  be  worked. 

Washing  the  nitrated  cotton  is  an  operation  of  great  im- 
portance, the  last  traces  of  acid  having  to  be  removed  by  it. 
The  washing  process  requires  from  10  to  12  hours,  and  dur- 
ing this  time  the  water  has  to  be  changed  up  to  sixteen 
times,  22  gallons  of  water  being  calculated  on  for  every  2.2 
Ibs.  of  dry  material. 

The  nitro-cellulose  having  been  sufficiently  washed  is 
returned  to  the  hydraulic  press,  and  its  content  of  water 
reduced  by  pressure  to  3G  per  cent.,  it  remaining  in  this 
condition  until  after  it  is  spun,  when  it  is  completely  dried. 
This  high  content  of  water  renders  it  perfectly  safe,  and  for 
further  working  it  is  simply  kept  in  vessels  protected  from 
dust. 

PREPARATION    OF    THE    COLLODION    SOLUTION. 

The  solution  of  the   nitro-cellulose  in  the   mixture  of 


214  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

alcohol  and  ether  is  effected  in  a  horizontal  iron  cylinder 
lined  with  tin,  and  capable  of  revolving  around  its  longi- 
tudinal axis.  A  mixture  of  equal  parts  of  95  per  cent, 
alcohol  and  ether  is  used  as  solvent,  and  about  100  quarts 
of  the  mixture  are  employed  for  every  48.4  Ibs.  of  dry 
nitro-cellulose. 

The  vessel  containing  the  nitro-cellulose  and  the  solvent 
is  uninterruptedly  kept  slowly  revolving  by  means  of  a 
mechanical  contrivance  until  solution  is  complete,  the  time 
required  being  from  15  to  20  hours.  A  small  quantity  of 
the  fluid  is  from  time  to  time  taken  from  the  vessel  by 
means  of  a  test-cock,  and  when  it  appears  perfectly  clear, 
without  any  turbidity  caused  by  minute  flakes,  the  solution 
is  of  the  proper  quality. 

However,  the  viscous  solution  nevertheless  contains  un- 
dissolved  or  incompletely-swollen  fibres  imperceptible  to 
the  naked  eye,  by  which  the  production  of  an  entirely 
uniform  thread  in  any  desired  quantity  would  be  rendered 
impossible.  For  the  removal  of  these  minute  fibres  the 
solution  has  to  be  filtered.  However,  with  a  fluid  of  the 
viscous  nature  of  nitro-cellulose  solution,  this  operation  can 
only  be  effected  with  the  use  of  very  strong  pressure  upon 
the  surface  of  the  fluid,  a  pressure  of  30  to  60  atmospheres 
being,  according  to  experience,  required  for  the  purpose. 

The  filtering  contrivance  consists  of  a  cylindrical  vessel, 
the  filtering  material  being  placed  upon  the  bottom,  a  layer 
of  fine  cotton  wadding,  0.39  to  0.59  inch  thick,  being  used 
for  the  purpose.  This  layer  of  cotton  wadding  is  enclosed 
between  two  sheets  of  finest  silk  gauze,  and  covered  on  both 
sides  with  tinned  metallic  cloth.  The  filter  has  a  capacity 
of  about  100  quarts  of  nitro-cellulose  solution,  and  having 
been  charged  with  fluid  and  closed,  air  under  pressure  is 
introduced  through  a  pipe  on  the  top,  the  pressure  being 
gradually  increased  to  such  a  degree  as  required  to  cause 
the  filtered  fluid  to  run  off  in  a  sufficiently  thick  stream. 

Defore  being  further  worked,  the  filtered  fluid   is  for  a 


ARTIFICIAL    SILK.  215 

certain  time  kept  in  glass  carboys,  each  holding  about  50 
quarts,  it  having  been  shown  by  experience  that,  as  regards 
its  capacity  of  being  spun,  it  thereby  gains  considerably  in 
quality.  The  cause  of  this  phenomenon  is  very  likely 
found  in  the  fact  that  during  storing,  a  thorough  intermix- 
ture of  all  the  particles  of  fluid  takes  place  so  that  the 
smallest  differences  in  the  quality  of  the  separate  portions 
of  fluid  are  removed.  Hence,  in  order  to  have  constantly 
collodion  of  the  best  quality,  a  certain  quantity  should 
always  be  kept  on  hand,  so  that  it  may  be  stored  for  a 
sufficiently  long  time  previous  to  being  spun. 

SPINNING    THE    COLLODION. 

For  the  production  from  the  perfectly  homogeneous 
collodion  of  a  thread  representing  artificial  silk,  an  appar- 
atus has  to  be  used,  which  is  furnished  with  extremely 
narrow  apertures  through  which  the  collodion  solution  is 
pressed.  The  thread  suspended  free  in  the  air  yields,  by 
evaporation,  the  ether  and  alcohol,  and  is  in  a  short  time 
changed  to  a  solid  thread,  which,  however,  still  possesses 
sufficient  elasticity  and  plasticity  to  allow  of  its  being 
drawn  out  by  slight  tension  to  a  still  thinner  thread,  which 
is  then  reeled  up  and  further  worked. 

For  the  production  of  the  thin  threads,  sieve-like  metal 
plates  may  be  used,  or,  what  would  appear  more  suitable, 
narrow  glass  nozzles.  The  disposition  of  the  spinning 
apparatus  used  in  factories  arranged  according  to  Char- 
donnet's  sj'stem  is  as  follows  : 

The  collodion  to  be  worked  is  contained  in  a  vertical, 
tin-lined  steel  cylinder,  provided  on  top  with  a  pipe  through 
which  air  under  pressure  may  be  introduced.  To  the 
lower  end  of  the  cylinder  is  secured  a  steel  pipe  furnished 
with  glass  spinners  placed  at  a  distance  of  about  0.78  inch 
one  from  the  other. 

The  glass  spinners  are  made  by  drawing  out  glass  tubes 
over  a  glass-blower's  lamp,  so  that  the  lower  opening  has  a 


216  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


diameter  of  only  ¥^  millimeter.  The  uniformity  of  the 
threads  being,  of  course,  dependent  on  the  aperture  of  all 
the  spinners  having  the  same  diameter,  great  care  has  to  be 
exercised  in  their  manufacture.  Every  finished  spinner 
must  be  examined,  as  to  its  diameter,  with  the  microscope, 
and  only  those  are  available  which  by  microscopical  meas- 
urement show  uniformity  of  diameter,  all  others  with  wider 
or  narrower  apertures  being  rejected  as  useless. 

The  spinners  of  proper  diameters  are  cemented  in  a  metal 
frame  and,  together  with  the  latter,  secured  to  the  horizon- 
tal pipe  of  the  apparatus.  By  gradually  increasing  the  air- 
pressure  upon  the  surface  of  the  collodion,  it  is  finally 
increased  to  such  a  degree  that  the  collodion  is  with  the 
proper  velocity  pressed  from  the  spinners.  The  pressure 
required  for  this  purpose  depends  on  the  viscosity  of  the 
collodion,  and  ranges  from  40  to  50  atmospheres. 

The  spinning  apparatus  was  originally  so  arranged  that 
the  fine  threads  pressed  from  the  spinners  passed  into  water 
mixed  with  \  per  cent,  of  nitric  acid.  However,  this  was 
found  to  be  entirely  superfluous  ;  the  threads  could  be  di- 
rectly worked  as  they  came  from  the  spinners,  coagu- 
lating almost  immediately  under  contact  with  air.  With 
the  assistance  of  contrivances  closely  resembling  the  reels 
on  which  natural  silk  is  wound  from  the  cocoons,  the 
threads  are  caught  and  reeled  up.  A  counter  records  the 
number  of  revolutions  made  by  the  reel,  and  the  diameter 
of  the  latter  being  known,  the  length  of  thread,  after  the 
reel  has  revolved  for  a  certain  time,  is  also  known.  In  this 
manner  an  unbroken  thread  many  thousand  meters  long 
may  be  produced,  but,  as  a  rule,  only  500  meters  (546.81 
yards)  are  wound  on  one  reel,  when  the  thread  is  taken  off 
and  brought  together  to  a  skein. 

By  the  solidification  of  the  threads,  the  total  quantity  of 
alcohol  and  ether  contained  in  the  collodion  passes  in  the 
form  of  vapors  into  the  air.  For  the  removal  of  these 
vapors  the  spinning  room  should  be  provided  with  a  very 


ARTIFICIAL    SILK. 


217 


powerful  airing  contrivance  by  which  the  air  loaded  with 
vapors  is  carried  off  and  replaced  by  fresh  air  from  the  out- 
side. For  this  purpose  a  suitable  number  of  electrically- 
driven  ventilators  revolving  with  great  rapidity  are,  as  a 
rule,  fixed  in  the  ceiling  of  the  spinning  room. 

THE    SPINNING    APPARATUS. 

The  main  features  of  the  arrangement  of  Chardonnet's 
spinning  apparatus  are  shown  in  Figs.  34  and  35.  The 
narrow  glass  tubes  a,  which  serve  as  spinners,  are  sur- 


Chardonnet's  apparatus  for  the  preparation  of  artificial  silk. 

rounded  by  a  pipe,  K,  filled  with  water,  and  are  fixed  upon 
the  joint  pipe,  B,  which  is  surrounded  by  two  channels,  0, 
in  which  hot  water  circulates.  The  lower  aperture  of  each 
spinner  is  surrounded  by  two  curved  spring-blades  which 
form  pincers,  m.  By  means  of  the  joint  lever  o  and  the 


218 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


curved  arms  p  p,  these  pincers  oscillate  constantly  up  and 
down  over  the  reels  or  spools  on  which  the  threads  are 
wound,  so  that  in  case  one  of  the  threads  should  break,  it  is 
immediately  caught  by  them  and  returned  to  the  reel  or 
spool.  So  long  as  the  thread  runs  without  breaking,  the 
pincers  move  up  and  down  empty.  The  revolving  brush, 
H,  cleans  the  pincers  on  the  upper  end  of  the  lever. 

FIG.  35. 


Chardonnet's  apparatus  for  the  preparation  of  artificial  silk. 

The  spindles  of  the  spools,  R,  which  serve  for  winding  up 
the  threads  just  spun,  sit  upon  the  loose  cheeks  of  the  revolv- 
ing axle  o.  They  carry  small  rolls  V,  which  are  in  contact 
with  the  surface  of  smaller  sheaves  A.  By  this  arrangement 
the  simultaneous  revolution  of  all  the  spools  is  secured,  and 


OF  THE 

UNIVERSITY  I 

OF 


ARTIFICIAL    SILK.  219 

the  cheeks  for  replacing  the  full  spools  with  empty  ones  are 
also  simultaneously  moved.  The  entire  spinning  apparatus 
is  enclosed  in  a  glass  case,  L  F,  through  which  a  current  of 
warm  air  is  constantly  passed  for  the  purpose  of  forcing  the 
vapors  of  alcohol  and  ether  to  the  condensing  vessels. 

The  first  of  these  condensing  vessels  contains  a  solution 
of  soda  in  water  upon  which  the  condensed  alcohol  floats. 
The  vapors  escaping  from  this  vessel  hold  much  ether,  but 
very  little  alcohol,  and  are  conducted  through  several  vessels 
containing  sulphuric  acid  which  absorbs  the  total  quantity 
of  vapors.  This  sulphuric  acid  is  utilized  for  the  prepara- 
tion of  ether. 

The  threads  obtained  in  the  manner  above  described  con- 
sist of  nitro-cellulose,  to  which,  however,  still  adheres  almost 
the  entire  quantity  of  water  (about  36  per  cent.)  originally 
remaining  in  the  pressed  nitro-cellulose.  This  content  of 
water  is  left  in  the  threads  till  they  are  finished  to  prevent 
otherwise  possible  spontaneous  ignition. 

The  next  step  in  the  operation  consists  in  throwing  or 
twisting  the  individual  threads,  and  finishing  them  by  dry- 
ing. The  latter  operation  is  effected  by  taking  the  thrown 
threads  from  the  reels  and  passing  them  through  a  room 
the  temperature  of  which  is  kept  at  113°  F.  While  the 
threads  pass  through  this  room  all  the  water  still  adhering 
to  them  is  evaporated,  complete  drying  being  insured  by 
keeping  up,  in  addition,  a  strong  current  of  air  during  the 
quite  rapid  passage  of  the  threads  through  the  room. 

Notwithstanding  its  beauty,  the  artificial  silk  thus  ob- 
tained would  not  be  of  any  practical  use  if  it  were  left  in 
this  condition.  It  consists  of  nitro-cellulose  and  being, 
therefore,  highly  inflammable,  a  fabric  made  of  it  would 
in  an  infinitely  short  time  be  reduced  to  ashes  by  a  spark 
falling  upon  it.  The  artifical  silk  is  therefore  subjected  to 
an  operation  to  which  the  term  denitration  has  been  applied, 
its  object  being  to  reconvert  the  nitro-cellulose  into  ordinary 
cellulose. 


220  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

This  denitration  constitutes  one  of  the  most  difficult  por- 
tions of  the  manufacture  of  artificial  silk,  because  it  has  to 
be  done  as  completely  as  possible,  without,  however,  im- 
pairing in  the  slightest  the  lustre  and  smoothness  of  the 
threads. 

Denitration  may  be  effected  by  conducting  the  threads  of 
nitro-cellulose  through  solutions  of  alkaline  sulphides,  and 
the  sulphides  of  potassium,  sodium  or  ammonium  may  be 
used  for  this  purpose.  However,  ammonium  sulphide 
seems  to  be  most  suitable,  it  causing  very  complete  denitra- 
tion without  attacking  the  silk  itself.  The  different  factories 
keep  the  composition  of  the  fluids  used  by  them  for  denitra- 
tion secret,  but  a  fluid  of  the  proper  quality  may  be  readily 
prepared  with  the  use  of  ammonium  sulphide  obtained  by 
saturating  concentrated  ammonia  with  sulphuretted  hydro- 
gen, and  allowing  it  to  stand  until  it  has  become  yellow. 
Ammonium  sulphide  which  has  turned  yellow  contains  the 
polysulphides  of  ammonium  in  solution,  and  they  appear 
to  be  especially  effective  in  denitration. 

The  ammonium  sulphide  obtained  in  the  above  manner 
is,  of  course,  too  concentrated  for  use,  and  to  obtain  a  deni- 
trating  fluid  of  the  proper  quality,  fluids  consisting  of  water 
to  which  a  certain  percentage  of  concentrated  ammonium 
sulphide  has  been  added,  must  be  employed.  The  opera- 
tion has  also  to  be  effected  at  a  certain  temperature,  deni- 
tration taking  place  much  more  rapidly  at  a  higher  tem- 
perature than  at  one  but  a  few  degrees  lower. 

The  correct  composition  of  the  denitrating  fluid  may  be 
recognized,  on  the  one  hand,  by  the  appearance  of  the  de- 
nitrated  threads  under  the  microscope ;  they  should,  after 
denitration,  be  as  smooth,  uniform  and  lustrous  as  before. 
If  the  fluid  has  been  too  concentrated  and  acted  too  vigor- 
ously, it  is  immediately  recognized  by  the  appearance  of 
the  threads  under  the  microscope ;  they  are  lustreless,  dull 
and  here  and  there  even  corroded.  The  correct  composi- 
tion of  the  denitrating  fluid  may,  on  the  other  hand,  also 


ARTIFICIAL    SILK.  221 

be  established  by  chemical  analysis,  which  should  show 
that  the  silk  contains  no  nitric  oxide  whatever,  or  that  the 
quantity  of  its  content  has  been  reduced  to  a  minimum. 

By  denitration  the  silk  acquires  a  yellow  color  and  has 
therefore  to  be  subjected  to  a  bleaching  process,  a  small 
quantity  of  chloride  of  lime  and  hydrochloric  acid  being 
used  for  the  purpose.  In  factories  working  according  to 
Chardonnet's  system,  400  grammes  (14.11  ozs.)  of  chloride 
of  lime  and  800  grammes  (28.21  ozs.)  of  hydrochloric  acid 
for  16  kilogrammes  (35.2  Ibs.)  of  artificial  silk  are  found 
sufficient. 

The  bleached  skeins  of  silk  are  freed  by  careful  washing 
from  adhering  bleaching  agent,  then,  as  far  as  possible,  de- 
hydrated in  a  centrifugal,  and  finally  dried.  The  product 
thus  obtained  is  of  a  pure-white  color,  has  the  feel  of  natural 
silk,  but  surpasses  the  latter  in  beauty  of  lustre. 

PREPARATION  OF  COLORED  ARTIFICIAL  SILK. 

Colored  artificial  silk  may  be  prepared  in  two  different 
ways,  namely,  by  direct  coloring  while  preparing  it,  or  by 
dyeing  the  finished  skeins.  The  first-named  process  has  the 
appearance  of  being  the  more  simple  one,  thus  deserving 
the  preference,  but  it  has  been  learned  by  practical  exper- 
ience that  the  more  suitable  way  is  to  prepare  first  the  white 
silk,  and  then  follow  the  same  method  used  in  dyeing  na- 
tural silk. 

Dyeing  the  artificial  silk  while  in  the  course  of  prepara- 
tion is  effected  by  simply  dissolving  the  coloring  matter  in 
the  collodion,  the  readily  soluble  aniline  colors  being,  by 
reason  of  their  richness,  especially  suitable  for  the  purpose. 
The  coloration  of  the  collodion  has  to  be  very  intense,  so 
that  every  one  of  the  extremely  thin  threads  appears  suffi- 
ciently dyed. 

The  mixture  of  the  coloring  matter  with  the  collodion 
has  to  be  effected  before  the  latter  is  filtered,  this  being  the 
easiest  way  of  coloring  the  solution  uniformly  throughout, 


222  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

so  that  the  threads  always  show  exactly  the  same  color. 
However,  with  the  use  of  colored  solutions  the  contents  of 
at  least  one  cylinder  have  to  be  used  all  at  once,  and  thus 
the  quantity  of  silk  of  a  determined  color  is  quite  limited. 

For  this  reason  the  production  of  silk  from  colored  solu- 
tions has  been  almost  entirely  abandoned,  white  silk  only 
being  prepared,  which,  after  having  passed  through  the 
processes  previously  described,  is  dyed  like  natural  silk. 
Artificial  silk  prepared  from  nitro-cellulose  possesses  the 
property  of  readily  fixing  the  coloring  matter,  and  nearly 
all  shades  of  color  can  be  produced  by  simply  immersing  it 
in  the  dye  solutions,  the  .process  being  exactly  the  same  as 
that  employed  in  dyeing  natural  silk,  and  at  present  aniline 
colors  are  preferably  used. 

A  comparative  table  of  the  properties  of  artificial  silk 
prepared  according  to  the  various  methods  will  be  given 
later  on,  and  hence  those  of  Chardonnet  silk  need  here  only 
be  briefly  referred  to.  As  regards  lustre,  it  surpasses  by  far 
the  finest  qualities  of  natural  silk,  and  when  worked,  either 
in  an  uncolored  or  colored  state,  into  fabrics,  it  produces 
more  beautiful  effects  than  tissues  of  genuine  silk.  How- 
ever, while  the  latter  is  distinguished  by  great  strength  and 
tenacity,  artificial  silk  possesses  these  properties  in  a  far  less 
degree.  By  taking  the  elasticity  of  natural  silk  at  100, 
that  of  the  best  quality  of  Chardonnet  silk  is  at  the  utmost 
66,  hence  only  about  two-thirds:  Fabrics  made  of  artificial 
silk  alone  would  not  prove  very  durable,  and  hence  in 
weaving  them,  pure  silk  or  another  fibre  is  generally  used 
for  the  warp  and  artificial  silk  for  the  woof. 

DU    VIVIER'S    ARTIFICIAL    SILK. 

This  process  for  the  preparation  of  a  product  closely 
resembling  in  appearance  natural  silk,  was  made  known  in 
1889.  It  differs  only  in  a  few  details  from  Chardon net's 
method,  nitro-cellulose  being  also  used  as  the  basis-material 
for  its  preparation. 


ARTIFICIAL    SILK.  223 

The  method  of  preparing  this  product  known  as  soie  de 
France  is  briefly  as  follows  : 

Cotton  or  in  place  of  it,  artificially-prepared  cellulose  is 
in  the  ordinary  manner  punned  by  treatment  with  alkalies 
— either  soda  or  ammonia — and  then  converted  into  nitro- 
cellulose. However,  instead  of  using  a  mixture  of  nitric 
and  sulphuric  acids,  Du  Vivier  falls  back  upon  the  old 
method  of  nitration  in  which  dry  saltpetre  and  sulphuric 
acid  are  used  as  nitrating  fluid,  and  effects  the  treatment  of 
the  cellulose  at  a  comparatively  high  temperature — 140°  to 
176°  F. — till  trinitro-cellulose  is  obtained. 

In  working  with  saltpetre  and  sulphuric  acid,  potassium 
sulphate  is  formed.  This  salt  being  distinguished  by  its 
comparatively  slight  solubility,  it  can  only  with  surety  be 
removed  from  the  nitro-cellulose  by  subjecting  the  latter  to 
a  thorough  treatment  with  water,  and  the  consumption  of 
wash  water  must  necessarily  be  still  larger  than  is  the  case 
in  Chardonnet's  process. 

The  solvent  for  the  nitro-cellulose  has  to  be  considered  as 
the  main  feature  of  Du  Vivier's  method.  He  uses  for  this 
purpose  highly  concentrated  acetic  acid  (glacial  acetic  acid) 
in  the  proportion  of  100  parts  of  it  to  7  parts  of  nitro- 
cellulose. The  nitro-cellulose  obtained  in  this  manner  is 
mixed  in  varying  proportions  with  a  fine  quality  of  glue 
(isinglass)  and  gutta-percha,  and  then  worked  into  threads. 
The  latter  are  conducted  through  various  baths  prepared 
from  solutions  of  metallic  salts — alumina  salts  and  subli- 
mate solutions  being  used — the  object  of  which  is  very 
likely  to  transform  the  glue  contained  in  the  mass  into  an 
insoluble  combination.  The  finished  threads  have  finally 
to  be  subjected  to  denitration  as,  like  other  nitro  cellulose 
silk,  it  would  otherwise  be  highly  inflammable. 

As  far  as  known,  Du  Vivier's  process  has  not  been  suc- 
cessfully introduced  in  practice.  Some  samples  of  the  silk 
submitted  for  examination  are  said  to  surpass  the  Char- 
donnet  product  in  beauty  of  lustre. 


224  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

Regarding  the  mechanical  pan  of  preparing  the  threads, 
nothing  need  to  be  said  here,  as,  with  the  exception  of 
slight  modifications,  it  can  only  be  carried  on  in  a  manner 
similar  to  that  described  more  fully  when  speaking  of 
Chardonnet's  process. 


The  third  process  for  the  manufacture  of  artificial  silk 
from  nitro-cellulose,  which  has  thus  far  become  known,  is 
that  of  Lehner.  It  is  now  practically  carried  on  on  a  large 
scale,  and  threatens  to  become  a  serious  competitor  of 
Chardonnet's  system. 

Lehner  also  starts  with  nitro-cellulose  capable  of  com- 
plete solution,  but  all  information  regarding  the  prepara- 
tion of  this  nitro-cellulose  is  wanting.  According  to  the 
patent,  dated  1890,  wood  spirit  (methyl  alcohol)  is  used  as 
solvent  for  the  nitro-cellulose,  and  to  this  solution,  a  solu- 
tion of  fibroin  is  added.  The  fibroin,  i.  e.,  the  fibrous 
portion  of  natural  silk,  is  obtained  from  waste  in  silk 
spinning  establishments,  it  being  purified  and  dissolved  in 
concentrated  acetic  acid. 

According  to  a  modification  made  public  later  on,  in 
place  of  fibroin  solution,  solution  of  rubber  prepared  from 
drying  oils,  may  be  added  to  the  nitro-cellulose  solution. 
The  solutions  mixed  in  certain  proportions — which,  how- 
ever, are  not  given — are  pressed  through  spinners,  and 
conducted  through  a  vessel  containing  petroleum,  chloro- 
form, or  oil  of  turpentine.  The  thread  coagulates  in  these 
fluids  so  far  as  to  acquire  a  thick,  gelatinous  condition,  thus 
representing  a  very  viscous  mass.  This  state  of  the  thread 
is  utilized  to  make  it  still  thinner  by  stretching,  when  it  is 
wound  on  reels. 

According  to  the  present  state  of  the  manufacture  of 
artificial  silk,  but  two  processes  for  its  production  from 
nitro-cellulose  which  can  actually  be  carried  on  a  large 
scale,  are  known,  namely  Chardonnet's  and  Lehner's.  It 


ARTIFICIAL    SILK.  225 

is  scarcely  to  be  expected  that  another  process  will  be  added 
to  them,  since  Pauly's  artificial  silk  and  lustra-cellulose  pre- 
pared from  viscose,  compete  to  such  an  extent  with  the 
products  prepared  from  nitro-cellulose,  that  this  competition 
will  very  likely  end  in  the  abandonment  of  the  manufac- 
ture of  artificial  silk  from  nitro-cellulose. 

DENITRATION    OF    ARTIFICIAL    SILK. 

The  absolute  necessity  of  denitrating  artificial  silk  pre- 
pared from  nitro-cellulose  is  one  of  the  weakest  points  of  the 
entire  process,  it  being  extremely  difficult  to  effect  denitra- 
tion  to  the  extent  required  without  impairing  the  beauty  of 
the  product. 

H.  Richter  has  made  exhaustive  investigations  regarding 
the  denitration  of  artificial  silk  from  nitro-cellulose,  and, 
according  to  his  statements,  denitration  as  effected  by  his 
method,  does  not  impair  in  any  way  the  qualities  of  the 
silk  as  regards  lustre,  etc.  The  pith  of  Richter's  method  is 
the  treatment  -of  the  silk  with  such  metallic  salts  as  have 
lower  and  higher  degrees  of  oxidation,  the  solutions  of 
the  lower  degree  of  oxidation  being  used  with  the  addition 
of  an  acid.  Among  the  metallic  salts  adapted  for  this  pur- 
pose, the  cuprous  compounds  are  said  to  be  most  suitable, 
complete  denitration  being  effected  by  cuprous  chloride  and 
cuprous  oxy chloride.  Besides  the  cuprous  compounds, 
there  may  be  used,  either  by  themselves  or  in  a  mixture  of 
them  :  Ferrous,  manganous,  chromous,  tungstous,  stannous, 
mercurous  salts,  and  the  ferro-cyanide  and  metallic  cyanide 
combinations. 

For  the  purpose  of  accelerating  the  denitrating  process, 
substances  which  cause  the  artificial  silk  to  swell  up  may 
be  added  to  the  fluid  and,  in  addition  to  alcohol  and  ether, 
mention  is  made  of  a  long  series  of  substances  as  being  suit- 
able for  the  purpose,  for  instance,  oil  of  turpentine,  glycer- 
ine, indifferent  hydrocarbons  and  their  derivatives,  rubber 
solutions,  and  particularly  isinglass.  It  is  claimed  that 
15 


226  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

such  additions  cause  denitration  to  progress  smoothly  and 
completely,  and  that  the  full  strength  of  the  fibres  is  pre- 
served. With  the  use  of  cuprous  salts  for  denitration,  such 
additions  are  said  not  to  be  required.  In  regard  to  the 
quantity  of  acid  to  be  used,  it  is  only  necessary  to  take 
enough  of  it  to  convert  the  lower  degree  of  oxidation  into 
the  higher  one. 

As  a  special  advantage  of  his  process,  Richter  mentions 
the  possibility  of  recovering  the  nitrogen  compounds,  espec- 
ially the  nitric  oxide,  which  are  separated  by  denitration. 
However,  according  to  our  view  of  the  matter,  the  recovery 
of  the  nitrogen  compounds  would  actually  pay  only  when 
denitration  is  effected  with  large  quantities  of  artificial  silk. 
For  this  purpose,  air-tight  vessels  would  have  to  be  used  for 
denitration,  from  which  the  nitric  oxide  evolved  is  con- 
stantly sucked  off,  and  then  oxidized  by  bringing  it  in  con- 
tact with  oxidizing  bodies  such  as  hydrogen  peroxide  or 
solution  of  potassium  permanganate.  The  nitric  oxide  may 
also  be  directly  conducted  into  sulphuric  acid  and,  after 
adding  an  adequate  quantity  of  nitric  acid,  this  acid  may 
again  be  used  as  denitrating  fluid.  The  oxy-salts  formed  in 
denitration  may  also  be  reconverted  into  the  lower  degree 
of  oxidation,  so  that  the  operation  can  be  constantly  carried 
on  with  a  given  quantity  of  the  metallic  salt. 

If,  for  instance,  cupric  salts  have  been  used,  the  fluid, 
after  denitration,  only  contains  cuprous  salt.  By  adding 
to  this  fluid  common  salt  and  conducting  sulphur  dioxide 
through  it,  the  cuprous  salt  is  again  reduced  to  cupric  salt. 
Reduction  is  effected  in  a  still  more  simple  manner  by  plac- 
ing copper  plates  in  the  acid  fluid.  In  a  similar  manner 
the  higher  degrees  of  oxidation  of  other  metals  may  by  suit- 
able reducing  agents  be  reconverted  into  the  lower  ones,  for 
instance,  stannic  chloride  by  ferrous  chloride. 

Some  methods  have  also  been  devised  with  the  object  in 
view  of  preparing  from  the  start  a  product  which  is  not  in- 
flammable and,  hence,  does  not  require  denitration.  Such 


ARTIFICIAL    SILK.  227 

a  process  has,  for  instance,  been  patented  in  England,  by 
A.  Peit,  according  to  which  100  parts  of  nitro-cellulose,  7 
parts  of  gum  solution  and  5  parts  of  stannous  chloride  dis- 
solved in  benzol  are  used.  What  is  to  be  understood  by 
gum  solution  is  not  entirely  clear  from  the  patent  specifica- 
tion, and  as  gum  solutions  cannot  be  combined  with  ben- 
zol to  a  homogeneous  fluid,  it  may  be  supposed  that  rubber 
is  meant.  It  has  thus  far  not  transpired  whether  Peit's 
process  has  anywhere  been  introduced  in  practice. 

From  the  present  state  of  the  industry  it  has  to  be 
acknowledged  that  artificial  silk  prepared  from  nitro- 
cellulose is  distinguished  by  a  beautiful  appearance,  as  well 
as  by  relatively  great  tenacity  and  elasticity.  The  mechan- 
ical portion  of  manufacture  has  also  been  brought  to  such 
perfection  as  to  allow  of  the  production  of  artificial  silk  on 
the  most  extensive  scale. 

However,  as  previously  mentioned,  the  process  has 'one 
weak  point,  in  that  denitration  is  absolutely  necessary,  and 
by  this  operation  the  beauty  of  the  product  will  remain 
unimpaired  only  when  the  greatest  care  is  exercised.  The 
particulars  regarding  the  operations  of  denitration  thus  far 
made  public  are  only  partially  satisfactory. 

Particular  attention  has  to  be  drawn  to  the  fact  that  the 
production  of  artificial  silk  from  nitro-cellulose  has  the 
decided  drawback  of  the  operation  being  by  no  means 
free  from  danger  to  the  workmen.  Notwithstanding  all 
the  precautionary  measures  taken  in  the  factories,  spontane- 
ous ignition  has  frequently  occurred,  and  in  one  case  at 
least  it  was  accompanied  by  explosive  phenomena.  That 
Jihere  is  never  absolute  safety  as  regards  spontaneous  ignition 
is  shown  by  the  behavior  of  nitro-cellulose  in  drying.  As 
mentioned  in  describing  the  manufacture  of  nitro-cellulose, 
the  latter  becomes  electrical  so  readily  that  the  passage 
over  it  of  a  warm  current  of  air  may  lead  to  the  formation 
of  such  a  large  quantity  of  electricity  as  to  cause  the  forma- 
tion of  a  spark.  Even  if  the  latter  be  never  so  small,  it  is  of 


228  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

sufficient  power  to  ignite  the  nearest  particles  of  nitro- 
cellulose, and  the  ignition  of  the  entire  mass  must  inevit- 
ably follow.  Hence,  in  the  production  of  textile  threads 
from  nitro-cellulose,  special  care  must  be  taken  that  up  to 
the  time  when  the  threads  are  subjected  to  denitration,  they 
contain  such  a  large  content  of  water  as  is  consistent  with 
the  operation,  because  spontaneous  ignition  of  the  nitro- 
cellulose can  only  under  these  conditions  be  positively 
prevented.  In  addition  to  this  precautionary  measure, 
attention  must  be  paid  to  the  health  of  the  workmen  by 
providing  means  for  carrying  off  the  vapors  of  ether  and 
alcohol  evolved  during  the  coagulation  of  the  threads.  The 
precautionary  measures  which  have  to  be  adopted  in  this 
respect  have  been  previously  referred  to. 


X. 

CELLULOSE  THREADS.    (CELLULOSE  ARTIFICIAL 
SILK  AND  LUSTRA-CELLULOSE.) 

SEVERAL  methods,  according  to  which  it  seems  feasible 
to  convert  cellulose  into  a  solution  from  which  textile 
threads  may  be  produced,  are  at  present  known,  and  some 
of  them  have  been  applied  to  the  manufacture  of  textile 
threads  on  a  large  scale.  As  will  be  seen  from  the  descrip- 
tions given  below,  these  methods  possess  decided  advantages 
over  the  process  in  which  nitro-cellulose  solution  is  used. 
These  advantages  are  so  great  that  from  a  purely  economical 
standpoint,  it  may  be  safely  predicted  that  these  methods 
will  more  and  more  gain  ground,  and  that  cellulose-silk 
will  finally  be  made  so  cheaply  as  to  exclude  the  profitable 
production  of  nitro-cellulose  silk.  The  main  advantage  of 
textile  threads  from  cellulose  is  undoubtedly  that  they  are 
no  more  inflammable  than  fabrics  of  any  other  kind  of 
cellulose,  for  instance,  cotton.  Another  advantage  is  that 
the  manufacture  itself  is  far  more  simple  than  can  possibly 
be  the  case  with  nitro-cellulose.  In  addition,  it  may  here 
be  remarked  that,  as  regards  lustre  and  beauty,  fabrics  of 
cellulose  threads  compare  favorably  with  nitro-cellulose  silk. 

While  cellulose  dissolves  in  a  number  of  fluids,  only  one 
solvent,  namely  cuprammonium,  need  here  be  considered. 
This  combination  has  for  a  long  time  been  used  by  micro- 
scopists  for  distinguishing  vegetable  tissues.  The  object 
under  the  microscope  is  moistened  with  cuprammonium 
solution  which  causes  the  portions  of  tissue  consisting  of 
cellulose  to  disappear,  they  being  dissolved  in  the  fluid. 

(229) 


230  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

The  residue  remaining  behind  consists  of  other  combina- 
tions. 

The  idea  of  utilizing  the  solubility  of  cellulose  in 
cuprammonium  for  the  preparation  of  textile  fibres  is  of 
modern  conception,  and  to  Dr.  Hermann  Pauldy,  of  Glad- 
bach,  is  due  the  merit  of  having  invented  a  process  by 
which  such  threads  can  be  produced  on  a  large  scale. 

DR.  FAULT'S  ARTIFICIAL  SILK. 

The  preparation  of  textile  threads  (artificial  silk)  accord- 
ing to  Dr.  Pauly's  method  includes  a  series  of  operations, 
which,  as  far  as  the  actual  production  of  the  thread  is  con- 
cerned, may  be  sub-divided  as  follows  : 

1.  Preparation  of  pure  cellulose. 

2.  Preparation  of  a  solution  of  cellulose  in  cuprammonium 
of  such  concentration  that,  when  pressed  through  apertures, 
a  thread  results  which  possesses  sufficient  tenacity  to  allow 
of  its  being  stretched  lengthwise. 

3.  Separation  of  the  cellulose  in  the  thread. 

4.  Washing,    drying,    throwing    of    the    thin    cellulose 
threads. 

To  these  operations  have  to  be  added  the  preparation  of 
the  cuprammonium  solution  and  the  recovery  of  the  copper 
from  the  fluids  used,  the  endeavor  being  made  to  regain  as  far 
as  possible  the  entire  quantity  of  copper  used  in  the  opera- 
tion so  that  the  same  quantity  is  in  constant  circulation  in 
the  factory. 

PURIFICATION    OF    THE    COTTON. 

The  cotton  to  be  used  has,  previous  to  its  solution  in 
cuprammonium,  to  be  subjected  to  a  thorough  cleansing 
process,  this  being  effected  in  a  manner  similar  to  that  pre- 
viously described.  Quite  pure  cotton  is  washed  in  a  wash- 
ing drum  with  soda  solution,  while  for  less  pure  material, 
dilute  caustic  soda  solution  is  used. 

The  cotton  treated  with  one  of  these  fluids  is  whirled  in 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).        231 

a  centrifugal,  thoroughly  washed  with  water,  then  again 
whirled  in  the  centrifugal,  and  finally  completely  dried. 
For  the  latter  purpose  artificial  heat  has  to  be  employed, 
otherwise  the  cuprammonium  solution  would  be  too  much 
diluted  by  the  water  contained  in  the  cotton,  the  conse- 
quence of  which  would  be  loss  of  viscosity. 

DISSOLVING  THE  COTTON  IN  CUPRAMMONIUM. 

The  cotton  when  perfectly  dry  is  dissolved  in  cupram- 
monium, the  preparation  of  which  will  be  described  later 
on.  For  45  to  50  grammes  (1.41  to  1.76  ozs.)  of  cotton,  1 
liter  (2.11  pints)  of  cuprammonium  is  used,  this  concentra- 
tion being  sufficient  to  yield  a  fluid  capable  of  being  spun. 

According  to  statements  made  public,  solution  is  to  be 
effected  in  an  apparatus  closely  resembling  a  montejus. 
However,  since  the  latter  apparatus  consists  of  only  a  single 
vessel  closed  on  all  sides,  in  which  the  fluids  are  forced  up- 
wards through  a  rising  pipe,  it  would  not  seem  very  well 
adapted  to  the  purpose  of  dissolving  the  cotton,  though  it 
might  answer  for  storing  the  solution  till  it  is  to  be  used. 

For  the  purpose  of  dissolving  the  cotton  as  rapidly  as 
possible  in  the  cuprammonium,  a  mechanical  contrivance 
of  such  a  character  is  required  that  the  cotton  is  kept  in 
constant  motion  and  that  fresh  portions  of  it  are  continu- 
ally brought  in  contact  with  the  solvent. 

An  apparatus  resembling  a  Hollander  but  constructed  in 
accordance  with  the  nature  of  the  mass  to  be  worked  in  it, 
would  appear  very  suitable  for  the  purpose  of  dissolving 
the  cotton.  The  elliptical  bottom  of  the  trough  of  the  hoi- 
lander  should  be  either  of  wood  alone,  or  preferably,  for  the 
sake  of  durability,  of  wood  lined  inside  with  stout  copper- 
sheet.  The  trough  should  be  furnished  with  an  air-tight 
lid  to  prevent  decomposition  of  cuprammonium  by  the 
evaporation  of  ammonia.  One  of  the  compartments  should 
be  furnished  with  a  grinding  contrivance  consisting  of  a 
corrugated  bottom-plate  and  a  corrugated  cylinder  revolving 


232  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

at  a  short  distance  above  the  bottom-plate,  and  effecting  the 
comminution  of  the  mass  passing  through  it.  The  bottom- 
plate,  as  well  as  the  cylinder  revolving  above  it,  should  be 
either  of  copper  or  another  material  not  attacked  by  the 
fluid.  Iron  or  steel  is,  in  this  case,  entirely  excluded, 
because  the  copper  contained  in  the  fluid  would  be  separ- 
ated from  it  in  metallic  form. 

Solution  is  effected  by  bringing  the  weighed  quantity  of 
pure  cotton  into  the  hollander,  closing  the  latter,  and  al- 
lowing cuprammonium  solution  to  run  in  slowly,  the 
mechanism  which  effects  the  revolution  of  the  cylinder  over 
the  bottom-plate  being  at  the  same  time  set  in  motion.  In 
the  commencement  of  the  operation  only  a  small  quantity 
of  the  solution  should  be  run  in,  so  that  the  cotton  becomes 
first  saturated  with  it  before  the  entire  quantity  is  intro- 
duced. By  the  continued  tearing  between  the  bottom-plate 
and  cylinder,  the  particles  of  cotton  are  uniformly  dis- 
tributed throughout  the  fluid,  solution  being  under  these 
conditions  effected  in  the  shortest  time  possible.  In  prac- 
tice, 10  hours  are  generally  calculated  on  as  being  required 
for  the  preparation  of  the  solution,  but  with  the  use  of  an 
apparatus  similar  to  the  one  above  described,  it  may  be 
effected  in  a  much  shorter  time. 

The  progress  of  solution  is  judged  by  the  appearance  of 
samples  taken  from  time  to  time  and  allowed  to  stand 
quietly  for  10  minutes  in  a  tall,  covered  glass  cylinder.  If 
solution  has  been  properly  effected,  the  fluid  is  perfectly 
clear  and  of  a  uniformly  blue  color  without  cloudiness.  If 
the  lower  portions  of  the  fluid  show  a  different  color,  or  a 
precipitate  is  noticed,  it  is  indicative  of  a  considerable  por- 
tion of  the  cotton  remaining  in  an  undissolved,  or  only  in 
a  very  much  swollen,  state.  The  manipulation  in  the 
hollander  has  then  to  be  continued  till  the  sample  shows  no 
longer  a  want  of  uniformity. 

Although  the  fluid  appears  to  the  eye  perfectly  uniform, 
it  may  nevertheless  contain  considerable  quantities  of  co.t- 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).       233 

ton  fibres  only  very  much  swollen  without  being  actually 
dissolved.  Such  fibres  would  make  the  solution  unsuitable 
for  spinning,  a  viscous  fluid  absolutely  free  from  solid 
bodies  being  only  adapted  for  that  purpose.  Hence,  the 
solution  must  by  all  means  be  filtered,  filtration  being,  in 
this  case,  also  effected  in  an  entirely  closed  apparatus  in 
which  the  fluid  stands  under  such  a  high  air-pressure  as  to 
be  forced  through  the  close  pores  of  the  filtering  body,  a 
substance  entirely  indifferent  towards  the  action  of  cupram- 
monium  being  used  for  that  purpose.  Cotton  is  unsuitable 
for  a  filtering  material,  since  by  the  action  of  the  cupram- 
monium  it  would  in  a  short  time  swell  up  so  much  that  no 
fluid  could  be  forced  through  it  even  by  the  strongest  pres- 
sure. Plates  of  compressed  asbestus-felt  with  pores  suffi- 
ciently close  to  retain  the  solid  bodies  suspended  in  the 
fluid  are  very  suitable  for  filtering  purposes.  The  residue 
remaining  upon  the  filter  consists  chiefly  of  the  more  solid 
portions  of  the  cuticles  of  the  cotton  fibres  and  remnants  of 
plasma. 

The  filter  is  fitted  up  in  a  similar  manner  to  that  de- 
scribed under  Chardonnet  silk.  In  a  boiler-plate  cylinder 
stands  a  vessel  of  sheet  copper  which  serves  for  the  reception 
of  the  fluid  to  be  filtered.  Upon  the  bottom  of  this  vessel 
lies  the  asbestus  plate  enclosed  in  two  plates  of  copper-wire 
cloth.  Below  the  filter-plate  the  copper  cylinder  terminates 
in  a  truncated  cone  and  is  connected  with  a  copper  vessel 
which  serves  for  the  reception  of  the  filtered  solution. 

The  pressure  upon  the  fluid  in  the  vessel  is  produced  by 
compressed  air,  and  should  be  of  sufficient  force  to  effect 
filtration  with  suitable  rapidity.  Solutions  of  cotton  in 
cuprammonium  being  by  far  less  viscous  than  nitro-cellulose 
solutions,  less  pressure  is  required,  one  or  a  few  atmospheres 
being  sufficient. 

If  the  pipe  leading  from  the  filter  be  allowed  to  enter  a 
montejus,  the  solution  collects  in  the  latter  and  may  be 
raised  by  air-pressure  through  the  rising  pipe  of  the  montejus 
into  the  vessel  in  which  the  spinning  apparatus  is  placed. 


234  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

SPINNING    THE    SOLUTION. 

The  spinning  vessels  closely 'resemble  those  used  in  Char- 
donnet's  system.  They  consist  of  closed  sheet-steel  cylin- 
ders lined  with  copper,  in  which  the  fluid  can  be  placed 
under  increased  pressure. 

The  contrivance  in  which  the  formation  of  threads  is 
effected  is,  however,  of  peculiar  construction.  The  solution 
of  cotton  in  cuprammonium  is  also  distributed  in  a  hori- 
zontal pipe  to  which  the  spinners  are  secured,  the  latter 
being,  however,  of  a  characteristic  shape.  They  are  placed 
obliquely  and  bent  slightly  upwards,  so  that  the  fluid 
emerging  from  them  ascends  upwards  in  an  oblique  direc- 
tion. The  apertures  of  the  spinners  lie  beneath  the  level 
of  a  fluid  consisting  of  water  containing  15  per  cent,  of  sul- 
phuric acid. 

The  spinners  through  which  the  solution  passes  into  the 
dilute  sulphuric  acid  are  in  construction  similar  to  those  of 
the  Chardonnet  system,  but  as  will  be  directly  explained, 
threads  of  a  considerably  smaller  diameter  than  that  of  their 
apertures  can  be  obtained  from  them. 

The  moment  the  cellulose  solution  passes  into  the  sul- 
phuric acid,  it  is  decomposed,  a  solution  of  cupric  sulphate 
(blue  vitriol)  and  ammonium  sulphate  being  formed.  The 
solvent  being  decomposed,  the  cellulose  must  separate  in  a 
solid  state,  this  separation  taking  place  in  the  form  of  a  soft 
cylinder  of  a  gelatinous  nature  which  possesses  a  high  de- 
gree of  extensibility.  This  behavior  is  utilized  for  making 
the  thread  still  thinner  by  stretching. 

The  threads — usually  18 — as  they  come  from  the  lead 
trough  containing  the  sulphuric  acid  are  run  through  a 
glass  gatherer  or  collector,  so  that  the  thread  thus  formed 
is  actually  composed  of  18  separate  threads.  Back  of  this 
gatherer,  revolves  with  suitable  velocity  a  glass  roll  on 
which  the  thread  is  wound  under  a  certain  tension,  thus 
being  stretched.  The  glass  roll  while  revolving  is  also  with 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).       235 

the  requisite  velocity  moved  sideways  so  that  the  thread  is 
wound  up  in  windings  one  alongside  the  other. 

The  cellulose,  by  reason  of  its  larger  content  of  water 
being  much  too  soft  to  stand  rinsing  off  before  being  brought 
upon  the  glass  roll,  washing  has  to  be  effected  upon  the 
latter  itself.  This  is  best  done  by  placing  a  number  of 
such  glass  rolls  in  a  mechanical  contrivance,  which  causes 
them  to  revolve  slowly  in  a  trough  constantly  supplied 
with  fresh  water,  in  which  they  remain  till  the  last  traces  of 
sulphuric  acid  have  been  removed. 

When  washing  is  finished,  the  cellulose  threads  are  dried 
at  a  higher  temperature  by  bringing  the  glass  rolls  into  a 
drying  room.  By  the  slight  contraction  the  threads  undergo 
in  drying,  their  fineness  and  lustre  are  still  further  enhanced. 

The  further  manipulation  by  mechanical  means  of  the 
cellulose  threads  prepared  in  the  above  described  manner, 
is  effected  in  exactly  the  same  way  as  in  silk-spinning 
works.  The  thread  is  wound  from  the  glass  rolls  on  spools, 
and  thrown.  The  finished  threads  suitable  for  spinning 
may  be  dyed  in  the  skein.  They  are  mordanted  in  various 
ways  according  to  the  coloring  matter  to  be  used,  and  left 
in  the  dye  bath  till  the  desired  tone  of  color  is  obtained. 

As  compared  with  the  product  prepared  from  nitro- 
cellulose, the  properties  of  the  artificial  silk,  or  rather  pure 
cellulose,  prove  very  satisfactory.  As  regards  tenacity  and 
elasticity,  it  is  at  least  equal  to  Chardonnet  silk,  and  pos- 
sesses the  rustle  characteristic  of  genuine  silk.  A  special 
advantage  of  Pauly's  silk  is  found  in  the  fact  that  its  pro- 
duction is  free  from  all  danger,  no  poisonous  vapors  being 
evolved,  and  the  use  of  a  substance,  like  nitro-cellulose, 
which  is  dangerous  to  handle,  is  excluded.  Finally,  Pauly's 
silk  does  not  require  denitration,  which  is  absolutely  neces- 
sary with  the  product  from  nitro-cellulose,  and  this  evi- 
dently constitutes  the  most  valuable  feature  of  the  process. 
With  reference  to  the  point  of  expense,  it  will  be  seen  at  the 
first  glance  on  comparing  Pauly's  method  with  the  nitro- 


236  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

cellulose  process,  that  the  cost  of  production  by  the  latter 
must  be  considerably  greater,  the  cellulose  having  first  to 
be  converted  into  nitro-cellulose,  and  then  as  far  as  possible 
again  reduced  b}T  denitration  to  cellulose.  From  the  ad- 
vantages enumerated  here,  both  as  regards  manufacture 
and  properties,  it  would  seem  that  Pauly's  method  will  in 
the  course  of  time  drive  nitro-cellulose  silk  out  of  the  field, 

E.  BRONNERT'S  PROCESS. 

This  method  for  the  preparation  of  textile  threads  from 
solution  of  cellulose  in  cuprarnmonium  differs  essentially 
from  Pauly's,  the  cellulose  being  first  converted  into  soda- 
cellulose  which  is  effected  with  caustic  soda,  and  then 
triturated  with  cupric  sulphate  (blue  vitriol).  A  double 
conversion  takes  place  thereby,  sodium  sulphate  being 
formed  and  a  loose  combination  of  cupric  hydrate  and  cel- 
lulose. By  treating  this  combination  with  ammonia,  a 
solution  possessing  a  considerable  degree  of  viscosity,  which 
it  retains  at  a  higher  temperature,  is  obtained,  and  conse- 
quently it  yields  good  threads  capable  of  being  spun. 

In  carrying  out  the  process,  it  is  necessary  to  use  the 
separate  substances  according  to  molecular  weights.  For 
162  parts  by  weight  (1  molecule)  of  dry  cellulose  in  a 
finely  divided  state,  80  parts  by  weight  of  pure  sodium 
hydrate  dissolved  in  500  parts  by  weight  of  water  are  used, 
the  cellulose  being  intimately  mixed  with  the  fluid.  In 
the  course  of  an  hour,  249  parts  (1  molecule)  of  finely 
powdered  crystallized  cupric  sulphate  are  added  to  the 
mass  and  the  whole  is  intimately  mixed,  a  rise  in  the  tem- 
perature being  carefully  avoided.  A  uniform  mass  of  a 
pale  blue  color  is  formed.  Concentrated  ammonia  is  then 
poured  over  the  mass,  in  such  quantity  that  for  every  mole- 
cule of  cupro-hydrocellulose,  16  to  20  molecules  of  am- 
monia are  used.  Solution  takes  place  immediately,  and 
the  greater  portion  of  the  sodium  sulphate  remains  behind 
undissolved. 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).       237 

The  further  working  of  the  solution  of  cellulose  in  cup- 
rammonium  prepared  according  to  this  method  is  exactly 
the  same  as  in  Pauly's  process  previously  described. 

PREPARATION    OF    CUPRAMMONIUM. 

Besides  purified  cotton,  cuprammonium  is  the  most  im- 
portant product  used  in  the  manufacture  of  artificial  silk 
according  to  Pauly's  method,  and  its  preparation  consti- 
tutes an  essential  part  of  the  entire  manufacture.  Com- 
mercial cupric  sulphate  or  blue  vitriol  is,  as  a  rule,  used  as 
the  initial  material,  but  in  buying  it,  it  must  be  taken  into 
consideration  that,  as  found  in  commerce,  it  is  frequently 
very  impure  and  contains  a  considerable  quantity  of  ferric 
sulphate.  A  product  almost  chemically  pure  is  only  avail- 
able for  our  purpose. 

For  the  preparation  of  cuprammonium,  cupric  sulphate 
is  dissolved  in  a  sufficient  quantity  of  water  to  form  a  sat- 
urated solution.  As  well  water  always  contains  a  certain 
quantity  of  carbonates,  which  cause  a  separation  of  cupric 
carbonate,  the  solution  is  not  clear,  but  more  or  less  of  a 
milky  turbidity.  This  turbidity  may,  however,  be  readily 
removed  by  carefully  adding  to  the  fluid  a  small  quantity 
of  sulphuric  acid  and  stirring  thoroughly,  the  separated 
cupric  carbonate  being  thereby  redissolved,  and  the  clear 
fluid  then  contains  only  cupric  sulphate  in  solution. 

For  the  sake  of  precaution,  the  solution  is  filtered  into 
another  vessel,  and  after  bringing  it  into  brisk  motion  by 
means  of  a  spatula,  ammonia  is  added,  a  voluminous  pale 
blue  precipitate  consisting  of  cupric  hydroxide  being  formed. 
After  each  addition  of  ammonia,  the  fluid  is  thoroughly 
stirred  and  a  small  sample,  previously  filtered  through 
paper,  tested.  If,  on  adding  to  the  fluid  in  the  test-tube  a 
drop  of  ammonia,  a  precipitate  of  cupric  hydroxide  is 
formed,  it  is  proof  of  all  the  copper  in  the  fluid  not  having 
been  separated  ;  and  more  ammonia  has  to  be  added. 

When  a  fresh  sample  remains  colorless,  and  after  the 


238  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

addition  of  a  drop  of  ammonia,  no  noticeable  changes  are 
observed  in  it,  it  is  proof  of  all  the  copper  having  been 
separated  in  the  form  of  cupric  hydroxide.  Care  must  be 
taken  not  to  add  a  larger  quantity  of  ammonia  than  abso- 
lutely necessary  for  the  precipitation  of  the  cupric  hydrox- 
ide, because  by  an  excess  of  ammonia  the  cupric  hydroxide 
just  separated  would  be  redissolved,  and  the  fluid  again 
acquire  a  deep,  dark-blue  coloration. 

When  precipitation  of  the  cupric  hydroxide  is  complete, 
the  contents  of  the  vessel  are  allowed  to  stand  quietly  till 
the  precipitate  has  settled  to  the  bottom.  The  colorless 
supernatant  fluid  consisting  of  solution  of  ammonium  sul- 
phate in  water  may  be  utilized  as  a  fertilizer. 

By  opening  tap-holes  placed  at  different  heights  in  the 
wall  of  the  precipitating  tank,  the  solution  of  ammonium 
sulphate  is  drawn  off  as  far  as  possible.  Clear  water  is  then 
poured  over  the  precipitate  and,  after  distributing  the  latter 
in  the  water  by  stirring,  it  is  again  allowed  to  settle.  The 
supernatant  clear  fluid  is  again  drawn  off,  and  this  washing 
of  the  precipitate  is  several  times  repeated  till  it  may  be  sup- 
posed that  all  the  ammonium  sulphate  has  been  removed. 
The  pasty  precipitate  is  then  brought  upon  large  cloths 
suspended  by  the  corners,  and  allowed  to  remain  upon  them 
till  no  more  water  drains  off ;  a  certain  quantity  of  water  is 
also  removed  by  squeezing.  For  the  purpose  of  deter- 
mining exactly  the  quantity  of  water  still  contained  in  the 
mass,  a  weighed  sample  is  dried  at  a  moderate  heat  and 
then  again  weighed  ;  the  loss  in  weight  gives  the  quantity 
of  water  still  contained  in  the  mass  and  from  it,  is  calculated 
the  content  of  cupric  hydroxide.  Drying  the  sample  used 
for  this  test  should  be  effected  at  a  temperature  not  exceed- 
ing 176°  F.,  the  cupric  hydroxide  being  readily  decom- 
posed by  heating,  to  black  cupric  oxide  and  water. 

The  cupric  hydroxide  is  now  brought  into  the  apparatus 
in  which  it  is  to  be  converted  into  cuprammonium.  This 
apparatus  consists  of  a  closed  vat  provided  with  a  stirrer 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).       239 

furnished  with  several  paddles.  While  the  stirrer  is  slowly 
revolving,  the  weighed  quantity  of  cupric  hydroxide  is 
brought  into  the  vat,  and  the  ammonia  is  then  allowed  to 
run  in.  The  cupric  hydroxide  dissolves  readily  to  a  clear, 
dark-blue  fluid. 

When  the  stirrer  has  for  some  time  been  kept  in  motion, 
a  small  sample  of  the  fluid  is  taken  from  the  vat  and  allowed 
to  stand  quietly  in  a  test-tube.  If  a  precipitate  is  formed  it 
is  indicative  of  the  total  quantity  of  cupric  hydroxide  not 
having  been  dissolved,  and  more  ammonia  has  to  be  added. 
Although  an  excess  of  ammonia  does  not  hurt,  it  is  a  useless 
waste  of  material.  The  solution  of  cuprammonium  is  made 
of  such  a  concentration  that  1  liter  (2.11  pints)  contains  be- 
tween 10  and  15  grammes  (0.35  to  0.52  ozs.)  of  copper,  the 
desired  concentration  being  determined  by  means  of  an 
aerometer.  Solutions  with  this  content  of  copper  are  capa- 
ble of  dissolving  between  45  and  50  grammes  (1.41  to  1.76 
ozs.)  of  cotton  in  1  liter  (2.11  pints)  and  the  resulting  solu- 
tions possess  sufficient  viscosity  to  yield,  when  decomposed 
by  sulphuric  acid,  a  thread  of  such  tenacity  as  to  allow  of 
its  being  wound  on  the  previously-mentioned  glass  roll. 

According  to  the  process  of  E.  Bronnert,  M.  Fremery  and 
J.  Urban,  the  preparation  of  solution  of  cuprammonium  as 
solvent  for  cellulose  is  effected  by  filling  a  tall  cylinder 
with  copper-turnings  and  ammonia,  and  allowing  cooled 
compressed  air  to  ascend  for  ten  hours  in  the  cylinder. 
During  this  time  the  temperature  of  the  fluid  should  not 
exceed  41°  F.,  and  for  this  reason  the  cylinder  is  furnished 
with  a  jacket  in  which  cooled  common-salt  solution  con- 
stantly circulates.  At  a  higher  temperature  the  dissolved 
cupric  hydroxide  would  rapidly  separate,  and  the  content 
of  copper  in  the  fluid  would  not  amount  to  over  2  to  2.5 
per  cent.  The  solution  thus  obtained  must  also  be  kept  at 
the  same  low  temperature  during  the  time  required  for  the 
solution  of  the  cellulose. 

The  solubility  of  cellulose  is  claimed  to  be  considerably 


240  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

facilitated  by  previously  subjecting  it  to  thorough  bleach- 
ing. For  this  purpose  it  is  for  18  hours  placed  in  a  15  per 
cent,  chloride  of  lime  solution,  then  washed  and  imme- 
diately brought  into  the  cuprammonium.  Cellulose  thus 
treated  dissolves  to  within  10  per  cent. 

The  mode  of  bleaching  mentioned  above  is  of  great  im- 
portance as  regards  the  quality  of  the  solution,  cellulose 
more  vigorously  bleached  yielding  a  solution  which  is  not 
sufficiently  gelatinous  for  the  purpose  of  producing  service- 
able textile  threads. 

Cellulose  also  very  readily  soluble  in  cuprammonium  is 
said  to  be  obtained  by  treating  it  in  the  same  manner  as 
for  the  preparation  of  vegetable  parchment :  Immersion  for 
a  short  time  in  quite  concentrated  sulphuric  acid,  and  then 
washing  with  water  for  the  complete  removal  of  the  acid. 
For  the  production  of  threads  from  a  solution  of  such  cellu- 
lose in  cuprammonium,  the  solution  emerging  from  the 
spinners  is  simply  precipitated  with  an  acid,  and  the  thread 
•can  be  immediately  wound  on  a  roll,  and  dried  at  104°  F. 

RECOVERY    OF    THE    COPPER. 

By  the  decomposition  of  the  cuprammonium  in  the  dilute 
.sulphuric  acid  when  the  solution  emerges  from  the  spinners, 
the  entire  quantity  of  copper  contained  in  the  fluid  remains 
behind  in  the  sulphuric  acid,  the  same  being  the  case  with 
the  ammonia.  Hence,  in  addition  to  cupric  sulphate  the 
fluid  contains  ammonium  sulphate,  and  the  copper  has  to 
be  recovered.  This  may  be  effected  in  various  ways,  and 
depends  on  whether  or  not  the  ammonium  sulphate  dis- 
solved in  the  fluid  is  to  be  utilized. 

The  simplest  plan  for  the  recovery  of  the  copper  is  to 
treat  the  fluid  with  iron  when  it  has  been  so  far  exhausted 
that  it  contains  only  a  very  small  quantity  of  free  sulphuric 
.acid.  By  moving  to  and  fro  sheets  of  iron  suspended  in  the 
fluid,  copper  in  the  form  of  a  loose  powder  is  separated,  a 
corresponding  quantity  of  iron  being  dissolved.  The  fluid 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).        241 

remaining  behind  then  contains,  in  addition  to  ammonium 
sulphate,  ferrous  sulphate  (green  vitriol)  in  solution.  The 
separated  copper  only  requires  washing  with  water,  and  by 
treatment  at  a  moderate  heat  with  hydrochloric  acid  can  be 
redissolved.  The  solution  which  then  contains  cupric 
chloride  may  be  immediately  used  for  the  preparation  of 
cupric  hydroxide. 

However,  another  plan  may  be  adopted  by  which  the 
ammonium  sulphate  may  also  be  recovered  and  utilized  by 
itself.  The  dilute  sulphuric  acid  in  which  the  decomposi- 
tion of  the  cellulose  solution  is  effected,  is  used  until  it  con- 
tains but  a  very  small  quantity  of  sulphuric  acid  in  a  free 
state,  when  it  is  replaced  by  fresh  acid.  The  fluid  is  then 
mixed  with  ammonia,  the  free  sulphuric  acid  present  being 
thereby  converted  into  ammonium  sulphate.  By  the  addi- 
tion of  still  more  ammonia  the  cupric  hydroxide  begins  to 
separate,  and  by  adding  the  correct  quantity  of  ammonia 
all  the  copper  present  may  be  separated.  The  precipitated 
cupric  hydroxide  is  again  used  for  the  preparation  of  solu- 
tion in  ammonia,  and  theoretically,  unlimited  quantities  of 
cellulose  can  be  brought  into  solution  with  one  and  the 
same  quantity  of  copper.  The  fluid  freed  from  copper  now 
contains  ammonium  sulphate  in  solution,  which  may  be 
utilized  by  itself,  the  simplest  plan  being  to  employ  it  as  a 
fertilizer,  as  the  crystallization  of  such  a  comparatively 
small  quantity  of  the  salt  would  not  be  worth  the  trouble. 


After  Chardonnet's  process  for  the  production  of  textile 
threads  from  nitro-cellulose  solution  became  known,  other 
patents  were  taken  out  which,  however,  are  essentially  only 
modifications,  the  same  having  also  been  the  case  with 
Pauly's  method,  but  the  principle  remains  intact.  In  all 
the  new  processes  solutions  of  cellulose  in  cuprammonium 
are  worked,  the  innovations  consisting  only  in  the  subse- 
quent treatment  of  the  thread  obtained,  which  by  this 
16 


242  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

treatment,  it  is  claimed,  acquires  greater  lustre,  fineness  and 
tenacity. 

ARTIFICIAL    SILK    ACCORDING  TO  M.  FREMERY   AND  J.   URBAN. 

The  process  patented  by  M.  Fremery  and  J.  Urban  is 
said  to  yield  threads  of  greater  lustre  and  tenacity  than 
those  produced  by  Pauly's  method.  All  the  operations  by 
this  process  up  to  the  production  of  threads  fit  to  be  spun 
may  be  omitted,  as  they  differ  in  nothing  from  Pauly's,  the 
modification  commencing  only  with  the  treatment  of  the 
thread  when  it  emerges  from  the  acid  fluid.  Without 
endeavoring  to  make  them  thinner  by  stretching,  the 
threads  while  in  a  wet  state  are  tightly  wound  on  cylinders 
and  allowed  to  dry  upon  them.  The  cylinders  have  quite 
a  large  diameter,  so  as  to  allow  of  a  considerable  quantity 
of  thread  being  wound  on  them,  and  also  of  attaining 
greater  tension  during  drying. 

The  thread  thus  produced  forms  a  soft,  gelatinous  mass 
very  rich  in  water.  By  gradually  yielding  water  to  the  air, 
its  diameter,  as  well  as  its  length,  is  decreased,  but  being 
tightly  wound  on  the  cylinder  quite  a  considerable  longi- 
tudinal strain  ensues,  whereby  it  gains  in  fineness  and 
smoothness.  However,  the  thread  is  dried  in  the  air  only 
up  to  a  certain  degree,  when  the  cylinder  is  brought  into  a 
room  heated  to  104°  F.,  in  which  it  remains  until  the 
thread  is  perfectly  dry  and  can  be  wound  on  spools. 

Drying  the  thread  in  the  above-mentioned  manner — first 
up  to  a  certain  degree  at  the  ordinary  temperature,  and  then 
with  the  use  of  a  higher  temperature — is  of  great  import- 
ance. If  on  coming  from  the  spinning  apparatus  it  were 
immediately  exposed  to  the  higher  temperature  it  would, 
without  tightening,  dry  to  a  brittle,  lustreless  product  of 
porcelain-like  appearance. 

According  to  observations  of  the  patentees  two  phases 
may  be  distinctly  observed  in  the  drying  process.  In 
the  beginning  a  considerable  quantity  of  water  evaporates 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).       243 

in  a  comparatively  short  time.  Evaporation  then  takes 
place  very  slowly,  so  that  it  may  be  supposed  that  a  certain 
quantity  of  the  water  is  chemically  combined  with  the 
cellulose.  This  water  may  be  rapidly  brought  to  evapora- 
tion with  the  use  of  a  higher  temperature,  but  in  this  case 
the  thread  becomes  brownish  and  loses  lustre  and  tenacity. 

This  drawback  may  be  avoided  by  submerging  the  cyl- 
inder for  a  short  time  in  water  heated  to  between  158° 
and  212°  F.,  or  by  allowing  a  current  of  steam  to  act  upon 
it.  This  treatment  is  claimed  to  separate  the  chemically 
fixed  water  from  the  combination,  and  the  process  of  drying 
is  then  effected  in  one-quarter  the  time  which  would  other- 
wise be  required. 

In  addition  to  this  innovation,  which  actually  relates 
only  to  the  mechanical  manipulation  of  the  cellulose  thread, 
E.  Bronnert,  M.  Fremery  and  J.  Urban  have  introduced 
another  modification  which  refers  to  the  production  of  the 
thread  itself.  Instead  of  using  for  the  decomposition  of  the 
cellulose  solution  in  cuprammonium,  a  fluid  which  contains 
only  15  per  cent,  sulphuric  acid,  as  is  the  case  in  Pauly's 
method,  they  employ  a  fluid  which  contains  between  30 
and  65  per  cent,  sulphuric  acid,  a  fluid  with  50  per  cent, 
sulphuric  acid  yielding,  according  to  their  statements,  the 
best  results. 

The  thread  passing  from  the  spinner  into  such  a  fluid 
becomes  immediately  so  firm  and  tenacious  that  the  very 
disagreeable  breaking  of  it  does  not  happen,  and  conse- 
quently it  can  be  allowed  to  emerge  with  great  rapidity 
from  the  spinners  and  wound  on  the  cylinder.  The  thread 
obtained  in  this  manner  is  then  further  treated  in  the  usual 
way,  and  yields  a  product  which,  as  regards  firmness, 
tenacity  and  lustre,  answers  all  requirements. 

The  effect  of  concentrated  acid  may  be  explained  as  fol- 
lows :  The  solution  of  cellulose  in  cuprammonium  is  de- 
composed the  moment  it  passes  into  the  sulphuric  acid, 
hydro-cellulose  being  separated.  However,  by  the  great 


244  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

affinity  of  concentrated  sulphuric  acid  for  water,  this  com- 
bination is  immediately  again  decomposed  and  pure  cellu- 
lose formed,  which  contracts  quite  considerably,  thus  form- 
ing a  much  firmer  and  more  tenacious  thread  than  is 
otherwise  the  case.  It  may,  however,  also  be  possible  that 
by  the  action  of  the  sulphuric  acid,  a  thin  layer  of  the  cellu- 
lose is  dissolved  upon  the  surface  of  the  thread  and  again 
separated,  when  the  latter  passes  into  less  concentrated 
acid,  the  thread  becoming  thereby,  so  to  say,  varnished. 

If  the  chemical  process  actually  runs  its  course  in  the 
above-described  manner,  it  has  a  certain  resemblance  to 
that  which  takes  place  in  the  manufacture  of  vegetable 
parchment.  By  the  immersion  of  the  paper  in  concentrated 
acid,  a  contraction  of  the  felted  cellulose  fibres  is,  on  the 
one  hand,  effected,  while  on  the  other,  a  solution  of  the 
uppermost  layer  of  cellulose  immediately  takes  place. 
From  this  solution,  when  brought  in  contact  with  water,  a 
substance  is  separated  which,  like  a  varnish,  lies  upon  the 
surface  of  the  paper,  firmly  cements  together  the  individual 
fibres  in  the  interior,  and  thus  effects  the  great  strength  of 
vegetable  parchment. 

ARTIFICIAL    HORSE-HAIR. 

When  thread  resembling  genuine  silk  in  appearance,  as 
closely  as  possible,  is  to  be  produced  from  cellulose  solu- 
tion, a  spinner  with  an  aperture  of  a  very  slight  diameter  is 
used  and  the  diameter  of  the  thread,  while  the  latter  is  still 
soft,  is  sought  to  be  further  reduced  by  stretching.  Char- 
donnet,  as  previously  mentioned,  uses  a  spinner  with  an 
aperture  only  j-f^  millimeter  in  diameter,  and  by  stretching 
the  thread,  while  soft,  its  diameter  may  be  considerably 
reduced.  By  the  use  of  a  spinner  with  a  larger  aperture, 
thread  of  a  larger  diameter  may  of  course  be  obtained, 
though  a  certain  limit  should  not  be  exceeded.  When  the 
thread  exceeds  a  certain  thickness,  the  decomposition  of  the 
combination  and  the  separation  of  pure  cellulose  do  not 


CELLULOSE  THREADS  (CELLULOSE  ARTIFICIAL  SILK).       245 

take  place  with  such  completeness  as  is  required  in  order 
to  obtain  a  uniform  product. 

For  the  production  of  uniform  threads  of  larger  diameter, 
another  method  must  therefore  be  adopted  which  is  essenti- 
ally as  follows :  Spinners  with  apertures  so  large  as  is  con- 
sistent with  the  preparation  of  a  uniform  thread  are  used. 
A  number  of  such  spinners  are  so  placed  that  the  threads 
emerging  from  them  touch  each  other,  just  after  they  have 
been  formed,  while  they  are  still  beneath  the  level  of  the 
fluid.  In  this  state — so  to  say,  at  the  moment  of  formation 
— the  threads  unite,  and  there  is  no  difficulty  whatever,  in 
thus  obtaining  threads,  which  as  regards  their  diameter, 
are  equal  to  horse-hair,  and  even  surpass  it. 

The  threads  thus  obtained  may  be  dyed  any  color  de- 
sired, and  are  claimed  to  be  available  for  all  purposes  for 
which  horse-hair  is  at  present  used.  In  the  textile  industry, 
such  threads  might  be  utilized  for  the  preparation  of  the  warp 
for  especially  strong  fabrics  capable  of  great  resistance,  for 
instance,  sail  cloth.  These  threads  are  claimed  to  be  especi- 
ally adapted  for  filaments  for  incandescent  electric  lamps, 
and  may  also  be  advantageously  used  for  making  the  in- 
candescent body  of  gas  light. 


XL 

TEXTILE   THREADS    FROM    VISCOSE    (THREADS 
FROM  LUSTRA-CELLULOSE.) 

VISCOSE  solution  when  exposed  to  the  air  coagulates  in  a 
short  time  to  a  solid  mass  consisting  of  cellulose,  and  to 
obtain  the  latter  in  a  perfectly  pure  state,  it  is  only  neces- 
sary to  remove  the  alkali  present  by  treatment  with  water. 
If  viscose  be  allowed  to  emerge  from  tubes  with  a  cylin- 
drical cross-section,  threads  suitable  for  textile  fabrics  are 
obtained. 

By  reason  of  the  great  simplicity  of  the  process  of  obtain- 
ing pure  cellulose  from  viscose,  much  attention  is  very 
likely  to  be  paid  to  the  production  of  textile  threads  from 
this  material.  As  shown  by  experiments  on  a  small  scale, 
such  threads  possess  exactly  the  same  properties  as  artificial 
silk  prepared  according  to  Pauly's  method — because  threads 
prepared  from  viscose  consist  of  the  same  body  as  Pauly's 
silk,  namely,  cellulose,  the  only  difference  being  in  the 
manner  of  producing  them.  As  shown  by  the  experiments 
above-mentioned,  thread  prepared  from  viscose  possesses  a 
surprisingly  high  degree  of  lustre,  and  the  term  lustra- 
cellulose  may  properly  be  applied  to  it. 

Experiments  made  on  a  somewhat  larger  scale  also 
yielded  very  favorable  results,  the  thread  exhibiting  a 
magnificent  silky  lustre,  and,  therefore,  viscose  also  would 
seem  to  have  a  great  future  for  the  manufacture  of  textile 
threads  and  fabrics.  The  cost  of  producing  the  threads  will 
very  likely  not  be  any  larger  than  in  working  according  to 
Pauly's  method,  and  is  certainly  far  less  than  that  of  arti- 
ficial silk  made  by  Chardonnet's  process. 

(246) 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).       247 

Threads  made  from  viscose  are  distinguished  by  an  ex- 
ceedingly small  diameter,  being  in  this  respect  at  least 
equal  to  the  finest  quality  of  natural  silk.  In  addition 
they  possess  great  lustre  and  considerable  strength,  yield- 
ing, when  woven,  fabrics  of  great  beauty  which,  without 
any  further  finishing,  may  be  called  glossy  stuffs  in  the 
actual  sense  of  the  word.  The  viscose  intended  for  the 
preparation  of  threads  may  be  colored  throughout  the  en- 
tire mass  by  simply  adding  coloring  matter  and  thus,  in  a 
single  operation,  textile,  and  at  the  same  time  dyed,  threads 
may  be  produced,  which,  after  being  thro\yn  in  the  usual 
manner,  may  be  woven  into  fabrics.  With  the  use  of  vis- 
cose not  dyed,  pure  white  fabrics  requiring  no  special 
bleaching  or  finishing  are  obtained. 

Since  for  the  production  of  textile  threads,  materials  are 
used  which  in  themselves  possess  but  little  value,  such  as 
old  purified  cotton,  or  waste  paper,  or  finally  bleached  cel- 
lulose from  wood,  the  raw  material  is  considerably  cheaper 
than  that  used  for  the  production  of  artificial  silk  from 
nitro-cellulose,  and  fabrics  of  lustra-cellulose  are  conse- 
quently cheaper  than  those  of  artificial  silk,  but  withal  of 
equal  beauty.  Together  with  Pauly's  artificial  silk,  they 
will  be  able  to  compete  triumphantly  with  artificial  silk 
from  nitro-cellulose. 

While  artificial  silk  from  nitro-cellulose  is  extraordinarily 
inflammable,  and  fabrics  manufactured  from  it  before  being 
brought  into  commerce  have  to  be  subjected  to  denitration, 
tissues  of  lustra-cellulose  are  no  more  inflammable  than 
ordinary  linen  or  cotton  fabrics,  because  they  consist  of 
pure  cellulose. 

The  factories  engaged  in  the  production  of  fine  threads 
from  viscose  keep  the  apparatus  used  for  the  purpose  a  pro- 
found secret,  but  the  construction  of  such  an  apparatus 
presents  no  difficulties,  many  portions  of  it  corresponding 
with  that  generally  used  for  the  preparation  of  artificial 
silk  threads.  It  is,  however,  of  the  utmost  importance  that 


248  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

the  viscose  should  be  used  in  the  form  of  a  solution  abso- 
lutely free  from  solid  bodies.  Many  viscose  solutions  ap- 
pearing perfectly  clear  to  the  eye,  may,  nevertheless,  contain 
entirely  unchanged  fibres  of  cellulose  or  nitre-cellulose, 
which  have  escaped  the  action  of  the  carbon  disulphide,  they 
being  invisible,  because  they  possess  quite  the  same  power  of 
refracting  light  as  viscose  solution  itself.  If  such  viscose 
were  to  be  forced  .through  the  spinning  apparatus,  one  after 
the  other  of  the  narrow  apertures  would  soon  be  found  to 
yield  no  thread  whatever,  and  the  apparatus  could  not  be 
put  in  activity,  again  even  with  the  use  of  the  highest 
pressure. 

In  working  on  a  small  scale,  the  preparation  of  a  perfectly 
clear  viscose  solution  presents  no  difficulties  whatever,  but 
solution  does  not  progress  quite  so  smoothly  when  operating 
on  a  larger  scale,  the  viscose  on  being  brought  in  contact 
with  water  swelling  up  very  rapidly,  and  the  swelled-up 
mass  preventing  the  access  of  water  to  the  interior  portions. 
Hence  to  effect  solution  in  a  short  time  a  mechanical  con- 
trivance has  to  be  used  by  means  of  which  the  viscose  is 
reduced  and  the  formation  of  tough  lumps  prevented.  A 
hollander  is  best  suited  for  this  purpose,  as  the  thorough 
mixing  of  the  solid  mass  with  water  can  be  effected  by  it  in 
the  most  complete  and  rapid  manner. 

The  trough  of  the  hollander  is  first  filled  with  the  quan- 
tity of  water  to  be  used  for  dissolving  a  fixed  quantity  of 
viscose,  and  the  mechanism  having  been  set  in  motion,  the 
viscose  to  be  dissolved  is  introduced  in  small  portions. 
The  whole  is  then  worked  till  a  uniform  viscous  mass  is 
formed  in  which  no  dark  spots  or  streaks  can  be  noticed 
with  the  naked  eye. 

However,  the  presence  of  undissolved  particles  can  to  a 
certainty  be  only  prevented  by  filtering  the  finished  viscose 
solution  before  introducing  it  into  the  spinning  apparatus. 
Filtration  of  a  fluid  of  such  viscous  nature  as  viscose  causes 
considerable  difficulties  which  may,  however,  be  overcome 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).       249 

by  the  use  of  an  apparatus  especially  constructed  for  the 
purpose.  As  filtering  material,  it  is  best  to  use  porous 
plates  of  cellulose.  These  plates  are  placed  upon  a  metal 
plate  perforated  like  a  sieve,  which  forms  the  bottom  of  a 
solidly  constructed  cylinder.  The  latter  is  furnished  with 
a  lid  fitting  air-tight,  and  by  means  of  a  pipe  is  connected 
with  a  condensing  air-pump.  The  cylinder  having  been 
filled  with  the  viscose  to  be  filtered,  the  lid  is  placed  in 
position  and  the  air-pump  set  to  work,  the  pressure  upon 
the  fluid  being  only  gradually  increased  to  prevent  the 
filter-plate  from  being  torn  asunder.  When  the  pressure 
has  attained  a  certain  height,  the  viscose  commences  to 
trickle  through  the  filter,  and  it  is  only  necessary  to  keep 
up  the  same  pressure  in  order  to  secure  a  uniform  flow  of 
the  fluid.  When  the  charge  in  the  filter  is  almost  ex- 
hausted, fresh  viscose  is  introduced  through  a  pipe  on  the 
side  of  the  cylinder,  the  operation  being  thus  continued  so 
long  as  the  filter  remains  effective.  When,  notwithstanding 
increased  pressure,  filtration  is  observed  to  become  more 
and  more  sluggish,  it  is  indicative  of  the  pores  of  the  filter 
being  much  obstructed,  and  the  useless  plate  has  to  be 
replaced  by  a  fresh  one.  For  the  purpose  of  dislodging  the 
last  remnants  of  viscose  contained  in  the  pores  of  the  filter- 
plate,  pure  water  is  introduced  into  the  cylinder  until 
nothing  but  water  runs  off. 

This  last  remnant  of  viscose,  which  is  quite  dilute,  is 
used  in  place  of  pure  water  for  the  preparation  of  fresh 
quantities  of  solution,  and  the  cellulose  plate  which  has 
become  useless  for  filtration,  is  employed  as  raw  material 
for  the  preparation  of  nitro-cellulose,  nothing  being  thus 
wasted. 

It  is  advisable  to  make  provision  for  the  direct  passage  of 
the  clear,  filtered  viscose  from  the  filter  into  the  reservoir 
of  the  spinning  apparatus,  to  prevent  it  from  being  changed 
by  contact  with  the  air. 

The  spinning  apparatus  consists  in  its  main  features  of  a 


250  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

thick-walled  metal  vessel  which  can  be  closed  air-tight,  and 
can  be  connected  with  an  air-compressing  pump.  In  the 
bottom  of  this  vessel  sits  the  so-called  spinning-plate,  by 
means  of  which  the  formation  of  extremely  thin  jets  of 
fluid  is  effected.  In  this  spinning-plate  are  fixed  a  larger 
number  of  extremely  narrow  glass  tubes  conically  enlarged 
above.  The  reservoir  having  been  filled  with  the  clear 
viscose  solution,  the  air-compressing  pump  is  set  in  motion, 
and  the  pressure  increased  to  such  an  extent  that  the  fluid 
is  with  a  certain  velocity  forced  from  the  narrow  apertures. 

The  same  pressure  must  be  maintained  throughout  the 
entire  spinning  operation,  because  only  in  this  way  can  jets 
of  fluid  be  made  to  emerge  evenly  from  the  spinning  aper- 
tures, and  this  is  of  the  greatest  importance  for  the  uni- 
formity of  the  threads. 

By  allowing  the  threads  emerging  from  the  spinning 
apertures  to  hang  down  free,  they  stretch  to  a  considerable 
extent  by  reason  of  the  viscous  nature  of  the  viscose.  The 
resulting  threads  are  of  a  still  smaller  diameter  than  the 
original  ones,  and  they  break  only  by  their  own  weight 
after  having  attained  a  certain  length.  It  being  desirable 
to  produce  threads  of  as  small  a  diameter  as  possible,  the 
length  to  which  they  may  hang  down  free  without  danger 
of  breaking  has  to  be  determined  by  experiments.  How- 
ever, provision  has  then  to  be  made  for  hardening  them  as 
rapidly  as  possible  so  that  they  may  be  reeled  up. 

While  viscose  coagulates  by  itself  in  the  air,  too  much 
time  would  in  the  case  in  question  be  required  for  the  pur- 
pose, and  it  must  therefore  be  sought  to  convert  it  in  as 
short  a  time  as  possible  into  a  solid  body — viscoid.  The 
transformation  of  viscose  into  viscoid  is  the  more  quickly 
effected  the  higher  the  temperature  to  which  it  is  exposed, 
and  the  viscose  threads  after  having  been  stretched  to  a 
certain  length  must  be  further  treated  according  to  this 
principle. 

This  may  be  accomplished  by  the  following  arrangement: 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).       251 

The  reservoir  containing  the  viscose  to  be  spun  is  placed  at 
a  higher  level,  and  the  threads  emerging  from  the  spinning 
plate  sink  down  free  in  a  shaft-like  space.  On  the  bottom 
of  this  space,  the  coagulated  threads  are  drawn  through  glass 
eyes  and  conducted  to  the  reels  on  which  they  are  wound. 
The  latter  contrivances  closely  resemble  those  used  in  silk- 
spinning  establishments  for  reeling  silk  from  the  cocoons. 
For  the  purpose  of  converting  the  fluid  viscose  thread  into 
the  solid  viscoid  thread,  a  current  of  hot  air  ascends  in  the 
shaft  through  which  the  threads  sink  down.  By  this  hot 
current  of  air  the  mass  is  solidified  and  the  greater  portion 
of  the  water  at  the  same  time  evaporated.  The  tempera- 
ture and  velocity  of  the  current  of  air  ascending  in  the  shaft 
have  to  be  accurately  regulated  and  must  be  adapted  to  the 
rapidity  with  which  the  viscose  is  forced  from  the  spinning 
apertures.  The  current  of  air  must  of  course  be  so  hot  that 
the  threads  on  reaching  the  lower  end  of  the  shaft  are  suffi- 
ciently firm  and  dry  to  allow  of  being  reeled  up.  On  the 
other  hand,  it  must  in  ascending  have  already  yielded  so 
much  heat,  that  the  viscose  emerging  from  the  spinning 
apertures  is  not  immediately  coagulated,  but  retains  suffi- 
cient viscosity  to  allow  of  the  thread  stretching  to  a  certain 
extent  in  sinking  down  before  reaching  the  layer  of  air  in 
which  it  is  entirely  coagulated. 

To  bring  about  the  co-operation  of  all  the  conditions  by 
means  of  which  threads  of  the  proper  quality  can  only  be 
obtained,  the  same  conditions  must  be  adhered  to  in  every 
particular.  Thus  it  is  by  no  means  immaterial  whether 
there  is  a  difference  of  a  few  degrees  in  the  temperature  of 
the  viscose  in  the  reservoir,  its  consistency — greater  or  less 
degree  of  viscosity — being  influenced  thereby,  as  well  as  the 
time  the  thread  requires  for  coagulation. 

Efforts  must,  therefore,  always  be  made  to  use  viscose 
solution  of  the  same  temperature,  and  the  apparatus  fur- 
nishing the  hot  current  of  air  should  be  so  arranged  that 
the  temperature  of  the  heated  air  dan  be  exactly  regulated, 


252  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

this  being  accomplished  without  difficulty  with  the  use  of 
the  so-called  rib-heaters.  The  heater  is  enclosed  in  a  box 
through  which  air  is  constantly  forced  by  a  small  ventilator. 
By  keeping  the  latter  running  uniformly  and  maintaining 
constantly  the  same  expansion  of  steam,  the  air  is  heated  in 
such  a  uniform  manner  that  the  temperature  shows  but 
exceedingly  slight  variations.  If  necessary,  even  the  latter 
may  be  overcome  by  furnishing  the  box  with  a  register  by 
means  of  which  the  strength  of  the  current  of  air  may  at 
will  be  increased  or  decreased,  and  the  temperature  in  the 
shaft  can  thus  be  almost  instantly  raised  or  lowered. 

The  viscose  threads  wound  on  the  reels  are  of  such  a 
small  diameter  that  they  cannot  be  worked  by  themselves. 
A  larger  number  of  them — how  many  depends  on  the  fine- 
ness of  the  fabric  to  be  made — are  therefore  taken  together, 
and  converted  by  mechanical  means  into  skeins  which  can 
be  woven,  being  further  worked  exactly  as  any  other  yarn. 

PREPARATION    OF    TEXTILE    THREADS    FROM  VISCOSE,  ACCORD- 
ING TO  STEARN. 

According  to  Ch.  H.  Steam's  patented  process,  textile 
threads,  as  well  as  thin  plates  of  viscoid,  may  be  directly 
prepared  by  a  simple  method  from  viscose  solution.  The 
threads  emerging  from  the  spinning  apparatus  are  immedi- 
ately allowed  to  drop  into  solution  of  ammonium  chloride 
(sal  ammoniac)  in  which  they  at  once  coagulate  and  can 
be  directly  reeled  up  or  thrown.  By  fitting  the  bottom  of 
the  vessel  containing  the  viscose  solution,  with  a  narrow  slit, 
in  place  of  the  narrow  apertures  which  furnish  cylindrical 
threads,  the  viscose  solution  is  obtained  in  the  form  of  a 
thin,  broad  band,  which  also  solidifies  immediately  in  the 
ammonium  chloride  solution.  The  thin  plates  thus  ob- 
tained may  be  used  for  writing  and  printing,  as  well  as  for 
photographic  purposes,  they  being  especially  suitable  for 
the  preparation  of  the  long,  narrow  strips  which  serve  for 
taking  pictures  for  the  cinematograph. 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).       253 

The  cellulose  threads  prepared  according  to  one  or  the 
other  process  have  to  be  carefully  washed,  by  being  repeat- 
edly brought  in  contact  with  fresh  quantities  of  water.  To 
be  quite  sure  of  all  the  alkali  having  been  entirely  removed, 
the  threads  are  finally  passed  through  pure,  highly  diluted 
acetic  acid,  and  then  dried  in  the  air.  The  acetic  acid 
which  is  not  fixed  evaporates  thereby,  and  the  threads  then 
cannot  contain  any  free  alkali. 

MILLAR'S  ARTIFICIAL  SILK  (GELATINE  SILK). 

While  in  all  the  previously-described  methods  for  the 
preparation  of  textile  threads  either  nitro-cellulose  or  cellu- 
lose solutions  form  the  basis-material,  in  Millar's  process, 
as  well  as  in  a  very  similar  one,  published  by  Hummel, 
glue  is  used  as  the  initial  raw  material.  By  reason  of  the 
great  viscosity  of  glue  solution  it  may  be  made  into  threads, 
and  the  glue  contained  in  them  can  by  suitable  treatment 
be  converted  into  an  insoluble  combination. 

The  textile  threads  thus  produced  have,  however,  not 
stood  the  test  as  compared  with  other  artificial  threads,  and 
we  may  here  confine  ourselves  to  giving  merely  the  outlines 
of  the  mode  of  manufacturing  them. 

According  to  Millar's  process,  2  Ibs.  of  glue  of  finest 
quality  (gelatine)  are  broken  up  in  small  pieces  and  allowed 
for  one  hour  to  stand  quietly  together  with  4  Ibs.  of  cold 
water.  The  mass  is  then  for  two  hours  heated  to  120.2° 
F.,  the  result  being  a  very  thick  solution  in  water  which, 
when  forced  through  narrow  tubes,  can  be  drawn  into 
threads.  The  latter  are  conducted  into  a  room  filled  with 
vapors  of  formaldehyde  whereby  the  glue  is  rendered  in- 
soluble. 

A  modification  of  Millar's  process,  consists  in  adding  to 
the  glue  solution  a  quantity  of  potassium  dichromate  equal 
to  about  2  per  cent,  of  the  weight  of  glue  used.  The 
threads  spun  from  the  solution  are  exposed  to  the  light 
whereby  the  glue  is  also  converted  into  a  combination  in- 
soluble in  water. 


254  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

While  the  threads  obtained  by  either  one  of  these  pro- 
cesses, present  quite  a  nice  appearance,  they  do  not  possess 
sufficient  flexibility  and  elasticity  to  be  utilized  for  tissues. 
If  a  thread  be  once  or  twice  bent,  and  then  placed  under 
the  microscope,  the  bent  places  will  be  seen  full  of  cracks, 
and  by  repeated  bending  the  thread  would  break.  A 
further  disadvantage  is  that  the  threads  swell  very  much 
in  moist  air. 

By  drawing  gelatine  threads  after  they  have  acquired  a 
certain  degree  of  solidity  through  solution  of  an  aluminium 
salt,  or  tannin  solution,  their  brittleness,  as  well  as  their 
tendency  to  swell  up  in  moist  air,  is  somewhat  reduced, 
but  the  resulting  product  cannot  bear  comparison,  as  re- 
gards beauty  and  strength,  with  cellulose  threads,  and  there 
is  very  likely  no  prospect  of  the  production  of  gelatine 
threads  which  might  be  available  for  practical  purposes. 

GENERAL    PROPERTIES    OF   TEXTILE     THREADS     PRODUCED    BY 
ARTIFICIAL    MEANS. 

The  textile  threads  produced  by  one  or  the  other  of  the 
processes  previously  described,  possess  properties  which  in 
many  respects  differ  essentially  from  those  of  genuine  silk 
or  of  cellulose  derived  from  plants,  and,  in  dyeing  as  well 
as  in  weaving,  they  have  to  be  differently  treated. 

Threads  from  nitro-cellulose,  as  well  as  from  pure  cellu- 
lose, possess  much  greater  lustre  than  natural  silk,  and,  in 
addition  to  this  high  lustre,  are  stiffer  and  more  elastic, 
these  properties  being  of  great  advantage  in  working  them. 

However,  on  the  other  hand,  the  manipulation  of  arti- 
ficial silk  is  rendered  very  difficult  by  the  fact,  that,  when 
brought  in  contact  with  water,  the  threads  lose  the  greater 
portion  of  their  tenacity,  the  latter,  as  shown  by  direct 
measurements,  being  reduced  to  J  and  even  to  TV  of  the  dry 
thread.  The  cause  of  this  phenomenon  is  that  the  threads, 
on  coming  in  contact  with  water,  swell  up  very  much, 
whereby  the  coherence  of  the  separate  particles  is  to  a  great 
extent  broken  up. 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).        255 

In  dyeing  threads  of  artificial  silk,  the  above-mentioned 
facts  have  to  be  taken  into  consideration,  and  moderately 
warm  dye-baths  of  a  temperature  not  exceeding  140°  F., 
should  only  be  used.  Great  care  must  also  be  exercised  in 
handling  the  skeins  in  the  dye-bath  to  avoid  breaking  off  a 
large  portion  of  the  threads.  By  reason  of  the  threads 
swelling  very  much,  they  take  the  dye  more  rapidly  than 
is  the  case  with  natural  silk,  and  for  delicate  shades  very 
dilute  dye  solutions  have  to  be  used,  there  being  otherwise 
danger  of  over-dyeing. 

When  dyeing  is  finished,  the  skeins  or  fabrics  must  by 
no  means  be  wrung  out  as  may  be  done  with  natural  tex- 
tile fabrics,  but  must  be  freed  from  adhering  dye-fluid  by 
whirling  in  a  centrifugal,  further  washing  with  water  being 
also  effected  with  the  latter  apparatus. 

As  regards  the  further  properties  of  artificial  textile 
threads,  the  microscope  furnishes  an  excellent  means  for 
their  examination,  and  with  its  assistance  genuine  silk  can 
immediately  be  distinguished  from  the  artificial  material  by 
the  form  of  the  latter,  which  in  itself  proves  it  to  be  an  arti- 
ficial product.  While  natural  silk  always  appears  as  a 
smooth  cylinder  of  uniform  thickness  with  only  a  few  cross 
stripes,  the  artificial  thread  never  possesses  such  uniformity, 
being  considerably  thicker  in  some  places  than  in  others. 
It  is,  as  a  rule,  not  perfectly  round,  but  more  or  less  flat- 
tened, this  being  especially  the  case  with  Chardonnet  silk, 
while  Pauly's  is  much  more  uniform,  its  shape  approaching 
more  closely  that  of  a  cylinder. 

The  difference  between  natural  and  artificial  silks  be- 
comes especially  noticeable  under  the  microscope  on  moist- 
ening the  sample  with  water.  While  natural  silk  does  not 
swell  up  to  a  noticeable  extent  by  remaining  even  for  a 
long  time  in  contact  with  water,  the  artificial  product  im- 
mediately commences  to  swell  up  and  acquires  a  width  J  to  J 
greater  than  when  dry. 

The  compilation  given  below  is  based  upon  micrometrical 


256  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

measurements,  and  shows  the  diameters  of  various  kinds  of 
natural  silk -in  a  swollen  state.  To  obtain  the  diameters  of 
the  threads  in  a  dry  state,  deduct  J-  to  J  from  the  figures 
given  : 

Mean.         Maximum. 

p  fj. 

Chardonnet  silk 45  to  60  100 

Fismes  silk 40  to  80  120 

Lebnersilk    .   .    . 60  to  90  135 

Pauly  silk 40  to  50  75 

Gelatine  silk 60  to  80  85 

Genuine  silk 9  to  15  20 

In  the  optical  way,  artificial  silk,  with  the  exception  of 
threads  prepared  from  gelatine,  can  also  be  immediately 
recognized  by  its  double  refraction  of  light.  Genuine  silk, 
to  be  sure,  possesses  the  same  power  of  refracting  light  but, 
with  some  practice,  the  difference  between  it  and  the  arti- 
ficial product  can  be  readily  discovered.  By  examining  in 
the  polarizing  instrument  a  thread  of  genuine  silk  in  such 
a  way  as  to  observe  different  portions  of  it,  the  same  color 
phenomena  will  always  appear.  However,  in  consequence 
of  its  irregularity,  such  is  not  the  case  with  artificial  silk, 
the  thicker  places  showing  entirely  different  colors  from  the 
thin  ones.  On  the  places  where  the  narrow  side  of  the 
flattened  thread  is  before  the  eye,  the  color,  as  a  rule,  is 
green  or  blue. 

The  richest  color  phenomena  are  observed  in  Lehner's 
silk,  the  separate  threads  showing  colored  longitudinal 
stripes  which  are  yellow,  red,  green,  or  steel-blue,  a  proof  of 
great  variations  in  their  dimensions. 

The  tenacity  of  the  threads  is,  as  a  matter  of  course,  a 
very  important  property  of  silk,  the  manner  of  working  it 
not  only  depending  on  it,  but  also  the  durability  of  the 
products  manufactured  from  it. 

Thus  far  no  artificial  silk  possessing  more  than  one-half 
the  tenacity  of  genuine  silk  has  been  produced.  The  com- 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).       257 

pilation  given  below  shows  the  tenacity  of  different  varieties 
of  silk  : 

Genuine  silk 100 

Chardonnet  silk 44 

Vivier  silk 29 

Pauly  silk 45  to  50 

Lehner  silk ' 68 

Dr.  Hassack  has  made  numerous  investigations  as  regards 
the  moisture  and  hygroscopicity  of  artificial  silks,  as  well  as 
the  products  themselves  in  general,  and  from  his  voluminous 
work  on  this  subject,  the  most  important  data  are  here  given. 

The  results  of  the  determination  of  moisture  calculated 
to  100  grammes  (3.52  ozs.)  dry  substance,  were  as  follows : 

Content  of  moisture 
in  per  cent. 

Indian  raw  silk 8.71 

Pres  de  Vaux  silk 11.11 

Fismes  silk 10.92 

Walstonsilk 11.32 

Lehner  silk  from  Glattbrugg 11.45 

Dr.  Pauly' s  cellulose-silk 9.20 

Gelatine  silk 13.98 

The  hygroscopicity  of  the  silks  was  determined  by  allow- 
ing the  dried  and  weighed  samples  to  remain  for  24  hours 
in  air  completely  saturated  with  steam,  when  they  were 
again  weighed.  The  absorption  of  water  in  per  cent,  was 
as  follows  : 

Italian  raw  silk 20.11 

Pres  de  Vaux  silk 27.46 

Fismes  silk ; 27.12 

Walston  silk 28.94 

Lehner  silk  from  Glattbrugg 26.45 

Cellulose  silk 23.08 

Gelatine  silk 45.56 

The  specific  gravity  of  artificial  silks  approaches  quite 
closely  that  of  genuine  silk,  gelatine  silk  almost  correspond- 
17 


258  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

ing  with  it,  while  that  of  the  other  is  10  to  11  per  cent, 
greater. 

ELASTICITY    AND    TENACITY    OF    ARTIFICIAL    SILK. 

These  investigations,  of  great  importance  for  the  utiliza- 
tion of  artificial  textile  fibres,  were  made  by  Dr.  Hassack  in 
the  following  manner : 

Pieces  of  thread  of  genuine  silk  and  of  the  silk  to  be 
tested  were  placed  in  the  tearing  apparatus  in  such  a  way, 
that  a  free  thread  3.93  inches  long  was  lying  between  the 
two  binding  screws,  and  the  length  of  the  thread  just  placed 
in  the  apparatus  without  being  stretched  was  accurately 
measured.  The  tension  was  then  increased  till  the  thread 
broke,  and  the  length  of  the  piece  of  thread  at  the  moment 
of  breaking  was  again  measured,  the  figures  showing  the 
load  at  the  moment  of  breaking,  as  indicated  by  the  instru- 
ment, being  at  the  same  time  noted.  After  every  test  one 
of  the  pieces  of  thread  was  placed  under  the  microscope,  and 
the  number  of  fibres  composing  it  were  counted,  so  as  to  be 
able  to  determine  the  separate  factors  for  a  single  spinning 
fibre. 

To  avoid  errors  every  determination  was  five  or  six 
times  repeated,  and  the  arithmetical  mean  of  the  results 
taken.  The  claim  of  being  correct  may  therefore  be  made 
for  the  figures  given  below.  The  results  were  for  : 

Genuine  silk  (Piemont-Organtin) 21.6  per  cent. 

Chardonnet  silk  from  Pres  de  Vaux 8.0 

Collodion  silk  from  Fisrnes 11.6 

Collodion  silk  from  Walston 7.9 

Lehner  silk 7.5 

Pauly's  cellulose  silk 12.5 

Gelatine  silk 3.8       " 

The  mean  results  obtained  by  the  breaking  tests  are 
given  in  the  table  below.  In  order  to  be  able  to  compare 
them  with  those  obtained  with  genuine  silk,  the  figures 
referring  to  the  latter  have  been  added.  The  silk  tested 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).       259 


was  of  medium  tenacity  and  the  titer  22  to  24  den.*  In 
the  last  column  of  the  table  the  relative  tearing  resistance 
of  the  samples  examined,  is  calculated  to  the  unit  titer  of 
100  den. 


Variety. 

Titer  in 
den. 

Relative 
breaking 
resistance. 

Calculated 
to  titer  of 
100  den. 

Expressed  in 
per  cent. 
Genuine  silk 
=  100. 

g- 

g- 

per  cent. 

Genuine  silk  .  .    . 
Chardonnet  silk  . 

22  to  24 
about    80 

57.5 
74.2 

250 
92 

100 
37 

Fismes  silk   .    .    . 

about  100 

71.7                    72 

28 

Walston  silk  -.  .    . 

about  120 

151.4 

126 

50 

Lehner  silk  .    .    . 

110  to  135 

171.8 

141 

56 

Cellulose  silk    .   . 

about  120 

197.6 

163 

66 

Gelatine  silk  .  .    . 

about  100 

63.0 

63 

25 

BEHAVIOR  OF  ARTIFICIAL  SILK  IN  A  CHEMICAL  RESPECT. 

Chemically  artificial  silks  differ  very  essentially  from 
the  genuine  product,  but  with  the  sole  exception  of 
threads  prepared  from  gelatine,  they  quite  agree  one  with 
the  other  as  regards  their  behavior  towards  chemical  re- 
agents. The  examination  of  artificial  silk  in  a  chemical 
respect  is  generally  made  with  the  assistance  of  the  micro- 
scope, it  being  possible  with  this  instrument  immediately 
to  distinguish  artificial  silk  alongside  of  genuine  silk  or 
another  fibre  in  a  tissue. 

The  principal  difference,  as  regards  their  chemical  be- 
havior, between  the  different  kinds  of  artificial  silk  known 
at  present,  depends  on  the  mode  of  their  preparation,  and 

*  1  den.  (1  denier)  =  0.10  g.  per  1000  m.  length  of  thread. 


260  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

the  difference  between  silk  consisting  of  pure  cellulose — 
Pauly's  silk  and  viscose  silk — and  that  made  from  nitro- 
cellulose has  above  all  to  be  determined. 

When  a  sample  of  the  threads  under  the  microscope  is 
touched  with  solution  of  diphenylamine  in  concentrated 
sulphuric  acid,  threads  prepared  from  nitro-cellulose  are 
immediately  colored  intensely  blue,  because  none  of  these 
silks  are  ever  entirely  denitrated.  This  reaction  is  so  dis- 
tinct as  to  be  plainly  perceptible  even  with  artificial  silk 
which  has  been  dyed.  Artificial  silk  of  pure  cellulose  is 
entirely  indifferent  towards  this  reagent. 

When  artificial  silk,  swelled  up  by  having  lain  in  water, 
is  moistened  under  the  microscope  with  absolute  alcohol  or 
concentrated  glycerin,  it  rapidly  regains  its  original  volume 
in  consequence  of  the  absorption  of  water  from  it. 

Swelled-up  threads  of  artificial  silk,  especially  such  as 
have,  in  addition,  been  boiled  in  water,  can  be  readily 
mashed  with  the  object-glass  and  broken,  this  being  espe- 
cially the  case  with  gelatine  silk. 

Artificial  silk  when  touched  with  concentrated  sulphuric 
acid  is  dissolved,  solution  taking  place  quite  rapidly  with 
nitro-cellulose  silk,  while  threads  of  pure  cellulose  first  swell 
up  very  much,  then  constantly  become  thinner,  and  finally 
disappear  entirely.  In  the  commencement  of  the  action  of 
the  sulphuric  acid,  cellulose  silk  exhibits  plainly  perceptible 
longitudinal  streaks.  Gelatine  threads  at  first  shrink  up 
very  much  by  the  action  of  sulphuric  acid,  then  swell  up, 
though  not  to  a  great  extent,  and  dissolve  only  when  strongly 
heated  with  the  sulphuric  acid.  By  concentrated  hydro- 
chloric acid,  fibrils  are  gradually  detached  from  nitro-cellu- 
lose silk  ;  the  threads  when  boiled  with  it  show  longitudinal 
and  cross  rents,  and  can  be  broken  into  small  sharp-cornered 
pieces  when  pressed  with  the  object-glass.  Gelatine  silk  is 
rapidly  attacked  by  hydrochloric  acid  and  in  a  short  time 
dissolved  by  it.  By  acetic  acid,  cellulose  silk,  as  well  as 
collodion  silk,  is  swelled  up,  while  gelatine  silk  is  completely 
dissolved  by  it. 


THREADS  FROM  VISCOSE  (FROM  LUSTRA-CELLULOSE).       261 

All  kinds  of  artificial  silk  are  in  a  short  time  dissolved  at 
the  ordinary  temperature  by  half-saturated  chromic  acid 
solution,  the  fluid  acquiring  a  brown  color.  Genuine  silk, 
to  be  sure,  is  also  dissolved  by  this  reagent,  but  consider- 
ably more  time  is  required  than  for  artificial  silk.  Vege- 
table fibres  not  being  attacked  by  chromic  acid,  it  can  in 
this  manner  be  at  once  determined  whether  only  the  woof 
of  a  piece  of  tissue  of  silk-like  appearance  consists  of  arti- 
ficial silk  (or  genuine  silk),  and  the  warp  of  threads  of 
vegetable  origin. 

Concentrated  soda  or  potash  lye  causes  cellulose  silk,  as 
well  as  collodion  silk,  to  swell  up  very  much  without  solu- 
tion being  effected  even  after  continued  boiling.  The  fluid, 
however,  is  colored  yellow.  Genuine  silk,  when  treated 
with  a  concentrated  alkaline  solution,  dissolves  at  the  boil- 
ing point,  the  solution,  however,  remaining  colorless. 
Gelatine  silk  shrinks  up  very  much,  and  then  passes  very 
rapidly  into  solution. 

Genuine  silk,  collodion  silk  and  cellulose  silk,  when 
treated  with  cuprammonium  solution,  swell  up  very  much 
in  the  fluid,  and  then  pass  gradually  into  solution.  With 
threads  consisting  of  nitro-cellulose,  the  small  bubbles 
almost  always  occurring  in  artificial  silk  are  plainly  visible. 
Cellulose  silk  swells  up  very  slowly,  and  the  longitudinal 
and  cross  streaks  are  more  distinctly  recognized  than  is  the 
case  in  water ;  finally,  complete  solution  takes  place.  Gel- 
atine silk  is  not  dissolved  by  cuprammonium,  but  is  colored 
pale  violet. 

Cellulose  and  nitro-cellulose  silks  may  also  be  plainly 
distinguished  from  genuine  silk  by  treating  the  threads  with 
alkaline  cupric  oxide  (glycerin)  solution.  Genuine  silk  is 
immediately  dissolved  when  heated  together  with  this  fluid 
to  176°  F.  Genuine  Tussah  silk  requires  somewhat  longer 
for  solution — about  one  minute — gelatine  silk  acting  in  the 
same  manner.  Nitro-cellulose  silk  and  pure  cellulose  silk 
are  entirely  indifferent  towards  this  reagent. 


262  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

Solution  of  iodine  in  potassium  iodide  solution  colors  all 
varieties  of  artificial  silk  intensely  red  to  brown,  the  color- 
ation, however,  disappearing  by  subsequent  treatment  with 
water,  though  nitro-cellulose  silk  exhibits  thereby  a  transient 
blue-gray  color.  With  the  use  of  iodine  solution  and  dilute 
sulphuric  acid,  genuine  silk  is  colored  yellow  by  the  fluid  ; 
nitro-cellulose  silk  acquires  a  deep  blue  color  shading  into 
violet,  while  cellulose  is  colored  pure  blue.  Gelatine  silk 
is  colored  yellow-brown  to  red-brown. 

Iodine  zinc  chloride  solution  colors  genuine  silk  yellow, 
and  collodion  silk  blue-violet,  while  cellulose  silk  only 
acquires  a  gray-blue  to  gray-violet  color.  Gelatine  silk  is 
colored  yellow  like  genuine  silk,  but  falls  immediately  to 
pieces,  while  the  structure  of  genuine  silk  remains  intact. 

Cellulose  silk  burns  in  somewhat  the  same  manner  as 
pure  cotton,  and  leaves  scarcely  any  residue,  while  collodion 
silk  leaves  behind  a  small  quantity  of  pure  white  or  gray 
ash.  Gelatine  silk  when  burning  gives  off  vapors  of  the 
same  disagreeable  odor  as  those  evolved  by  burning  glue. 


XII. 

CELLULOID. 

THIS  peculiar  substance  was  first  prepared,  in  1869,  by 
Hyatt,  of  Newark,  New  Jersey,  and  the  original  process 
used  by  him  is  said  to  be  at  present  employed — though 
probably  with  many  modifications — in  many  factories. 

Celluloid  is  distinguished  by  various  properties  which 
render  it  available  for  many  industrial  purposes,  and  there 
is  scarcely  another  substance  so  well  adapted  for  the  imita- 
tion of  various  bodies ;  such  as  tortoise  shell,  ivory,  coral, 
etc.  These  imitations  can  be  made  in  such  perfection  that, 
judging  solely  by  their  appearance,  they  frequently  cannot 
be  distinguished  from  the  genuine  bodies.  In  addition  to 
these  applications,  which  relate  more  or  less  to  the  produc- 
tion of  fancy  articles,  celluloid  has  found  its  way  into  sev- 
eral industries.  It  forms  at  present  a  very  important 
material  in  the  manufacture  of  sets  of  artificial  teeth,  and  it 
is  also  frequently  made  use  of  for  the  production  of  cliches. 

Although  the  physical  properties  of  celluloid  are  ac- 
curately known,  its  chemical  nature  is  thus  far  not  under- 
stood, it  being  uncertain  whether  it  is  a  chemical  combina- 
tion at  all,  or  only  a  mixture  of  certain  bodies  possessing 
the  peculiar  physical  properties  on  which  depends  its  great 
applicability.  Hence,  from  the  present  state  of  our  knowl- 
edge, celluloid  has  to  be  considered  an  intimate  mixture  of 
the  substances  used  in  its  preparation.  However,  it  may 
here  be  remarked  that  the  nitro-cellulose  contained  in  cel- 
luloid, strange  to  say,  loses  entirely  its  explosive  power,  and 
is  simply  inflammable. 

Celluloid  consists  essentially  of  an  intimate  mixture  of 

(263) 


264  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

soluble  nitrocellulose  (collodion  gun-cotton)  with  camphor. 
As  the  mixture  permanently  retains  the  penetrating  odor 
of  camphor,  the  use  of  the  product  for  various  purposes  is 
made  impossible,  and  it  has  been  sought  to  replace  the 
camphor  by  substances  entirely  odorless  or  of  a  less  intense 
odor.  This  object  has  been  partially  attained,  and  celluloid 
masses  entirely  free  from  odor  are  at  present  prepared. 

Several  methods  for  the  preparation  of  celluloid  are 
known,  and  they  may  be  designated  as  dry  and  wet  pro- 
cesses. According  to  the  dry  process  which  was  used  by 
Hyatt,  the  substances  constituting  the  mass  are  simply 
combined  by  mechanical  means — kneading,  rolling  and 
pressing.  In  the  wet  process,  fluids  capable  of  dissolving 
collodion-cotton  as  well  as  camphor  are  used.  When  the 
solutions  have  been  prepared,  the  solvent  is  allowed  to 
evaporate,  whereby  the  celluloid  remains  behind,  and  is 
then  further  worked  by  mechanical  means. 

As  regards  the  value  of  the  separate  methods,  it  may  be 
said,  that  they  all  yield  a  product  of  equal  quality  and  it  is 
only  a  question  of  which  is  the  cheapest.  The  purely 
mechanical  process  has  the  undisputable  drawback  of  a 
number  of  quite  complicated  machines  being  required,  and 
working  the  masses  takes  considerable  time  and  power. 

The  process,  in  which  the  substances  to  be  combined  are 
used  in  the  form  of  solutions,  requires  but  a  small  expendi- 
ture of  power ;  however,  a  very  large  portion  of  the  solvent 
is  unavoidably  lost  by  evaporation. 

With  the  use  of  suitable  auxiliary  contrivances,  the  loss 
of  solvent  by  evaporation  may  be  considerably  reduced  by 
condensing  the  greater  portion  of  the  vapors  to  fluid,  as  will 
be  explained  below,  and  for  this  reason  the  wet  process 
would  appear  to  deserve  the  preference. 

Although  various  methods  for  the  preparation  of  celluloid 
have,  in  the  course  of  time,  become  known,  most  of  them 
have  proved  to  be  only  immaterial  modifications  of  the  main 
process.  The  manufacturers  very  likely  introduced  these 


CELLULOID.  265 

modifications  simply  for  the  purpose  of  not  coming  in  con- 
flict with  the  owners  of  the  patents  for  the  fabrication  of 
celluloid  according  to  one  of  the  chief  processes. 

With  regard  to  the  methods  used  for  the  manufacture  of 
celluloid,  we  may  distinguish  : 

1.  The  dry  method  or  Hyatt' 's  process.     In  this  method  the 
wet   soluble    nitro-cellulose    is   by   rolling   combined   with 
camphor  to  a  homogeneous  mass. 

2.  The  wet  methods.     According  to  the  solvent  employed, 
several  methods  may  be  distinguished,  namely  : 

a.  Magnus's  process.     This  is  based  upon  dissolving  col- 
lodion-cotton and  camphor  in  ether,  and  evaporating  the 
ether  by  heating  the  solution. 

b.  Process  employed  by  the  factory  at  Stains,  near  Paris. 
This  is  based  upon  the  fact  that  collodion-cotton  and  cam- 
phor are  also  soluble  in  methyl  alcohol,  and  that  the  latter 
may  therefore  be  used  to  effect  solution.     By  both  of  these 
wet  processes,  celluloid  is  obtained  which  in  itself  is  very 
homogeneous  and  requires  mechanical  manipulation  only 
for  a  short  time  to  render  it  fit  for  further  working. 

PREPARATION    OF    THE    COLLODION-COTTON. 

The  principal  requisite  for  the  manufacture  of  celluloid 
is  the  use  of  a  nitro-cellulose  completely  soluble  in  the 
known  solvent.  As  regards  the  preparation  of  such  a  pro- 
duct, the  reader  is  referred  to  what  has  been  said  in  this 
respect  in  describing  the  manufacture  of  artificial  silk  ac- 
cording to  Chardonnet's  method.  It  may  be  repeated  that 
in  working  according  to  one  of  the  wet  processes,  the  use  of 
a  perfectly  soluble  product  is  of  the  utmost  importance. 

When  working  with  freshly  prepared  collodion  cotton,  its 
complete  solubility  has  to  be  ascertained  by  treating  a  small 
sample  with  the  solvent.  If  the  test  shows  the  collodion 
cotton  not  to  be  completely  soluble,  it  may  nevertheless  be 
used  for  the  manufacture  of  celluloid,  but  the  solution  must 
by  all  means  be  filtered,  though  filtration  need  not  be  so 


266  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

thorough  as  when  the  collodion  is  to  be  used  for  the  manu- 
facture of  threads.  For  the  purpose  of  filtration  it  suffices 
to  force  the  solution  under  slight  pressure  through  a  layer 
of  cellulose,  0.59  to  0.78  inch  thick,  in  order  to  obtain  a 
fluid  in  which  the  camphor  may  be  dissolved. 

According  to  the  original  statements  by  Hyatt,  collodion- 
cotton  suitable  for  the  purpose  of  preparing  celluloid  can 
only  be  obtained  by  using  for  nitration  an  extraordinarily 
fine  quality  of  paper  consisting  of  pure  cellulose.  Hyatt  is 
said  to  have  employed  for  this  purpose  the  finest  quality  of 
tissue-paper  torn  into  small  pieces  by  a  special  machine. 
These  pieces  were  then  treated  with  nitrating  fluid. 

It  will  be  readily  understood  that  with  the  use  of  such 
an  expensive  raw  material  as  a  fine  quality  of  tissue-paper, 
the  cost  of  producing  collodion-cotton  would  be  very  much 
increased,  and  it  would  be  impossible  to  furnish  celluloid 
articles  at  the  low  price  at  which  they  are  at  present 
brought  into  commerce.  It  has,  however,  been  shown  that 
for  the  manufacture  of  celluloid,  collodion-cotton  prepared 
from  any  kind  of  cellulose  may  be  used,  provided  the  latter 
has  been  subjected  to  sufficient  purification. 

PREPARATION  OP  CELLULOID  ACCORDING  TO  HYATT. 

The  collodion-cotton,  carefully  freed  from  acid,  is  as  far  as 
possible  dehydrated  by  the  use  of  a  powerful  press,  then 
reduced,  and  completely  dried.  It  is  not  stated  how  drying 
is  to  be  effected,  but  the  process  described  for  the  prepara- 
tion of  nitro-cellulose  may  be  employed.  The  dry  collodion- 
cotton  is  carefully  triturated,  mixed  with  camphor  and 
subjected  to  further  treatment  by  mechanical  means.  This 
account,  as  will  be  seen,  gives  a  very  meagre  description  of 
the  manufacture  of  celluloid,  no  data  regarding  the  manner 
of  mixing  the  collodion-cotton  with  the  camphor  being  fur- 
nished, nor  is  any  reference  made  as  to  the  proportions  in 
which  the  materials  are  to  be  mixed.  A  somewhat  better 
insight  into  Hyatt's  process  is  afforded  by  the  following 
description  : 


CELLULOID.  267 

The  collodion-cotton  previously  carefully  washed  is 
ground  fine  in  a  hollander,  and  converted  into  quite  a  solid 
cake  by  removing  the  water  by  pressure.  This  cake  is 
again  reduced  and  mixed,  under  water,  with  camphor. 
Mixture  being  complete,  the  mass  is  kneaded  and  rolled  by 
mechanical  means.  The  object  of  this  manipulation  is 
probably  to  bring  the  particles  of  collodion-cotton  and 
camphor  into  still  more  intimate  contact,  and,  in  addition, 
to  cause  evaporation  of  a  large  portion  of  the  water  con- 
tained in  the  mass.  The  latter  having  now  become  quite 
solid,  is  subjected  to  a  very  high  pressure  whereby  more 
water  is  removed,  and  the  combination  of  the  mtro-cellulose 
with  the  camphor  completed. 

The  mass  is  contained  in  a  jacketed  cylinder,  the  bottom 
of  which  is  formed  by  the  piston  of  a  hydraulic,  press. 
While  the  latter  is  at  work,  steam  is  introduced  into  the 
space  between  the  jacket  and  the  cylinder,  and  the  temper- 
ature is  gradually  raised  till  the  contents  of  the  cylinder 
are  heated  to  266°  F.  Although  at  this  temperature  cam- 
phor has  already  great  tendency  towards  vaporization,  by 
reason  of  the  state  of  fine  division  in  which  it  is,  in  conse- 
quence of  the  previous  operation,  the  vapors  evolved  can 
only  spread  to  the  particles  of  collodion-cotton  lying  next 
to  them.  Hence,  this  treatment  at  a  higher  temperature 
and  at  a  high  pressure  can  probably  be  only  viewed  in  the 
light  of  making  the  mass  finally  and  completely  homo- 
geneous. 

With  the  use  of  a  mixture  consisting  only  of  collodion- 
cotton  and  camphor,  the  cylinder,  when  the  above-mentioned 
temperature  has  been  reached,  contains  a  colorless  mass.  In 
the  hot  state,  this  mass  possesses  a  very  high  degree  of  plas- 
ticity, but  on  cooling  to  the  ordinary  temperature,  becomes 
firm  and  quite  hard.  In  the  state  in  which  it  comes  from  the 
hydraulic  press  it  can  be  rolled  out  to  plates  of  any  thick- 
ness, or  pressed  in  moulds,  being  left  in  the  latter  till 
cooled  to  the  ordinary  temperature. 


268  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

Celluloid  being  a  substance  which  can  be  dyed  any  de- 
sired color,  as  well  as  mixed  with  pulverulent  materials, 
articles  differing  very  much  in  appearance  may  be  made 
from  it.  The  admixture  of  the  foreign  bodies  may  be 
effected  previous  to  bringing  the  mass  into  the  hot  press,  or 
when  it  is  taken  from  the  latter.  In  the  latter  case,  the 
celluloid  is  rolled  out  into  thin  plates  upon  which  the  pul- 
verulent substances  are  scattered,  and  rolling  is  repeated 
until  a  perfectly  homogeneous  mass  is  obtained. 

Regarding  the  quantities  of  the  two  fundamental  con- 
stituents of  celluloid,  it  may  be  stated  that  for  every  two 
parts  of  collodion-cotton  one  part  of  camphor  is  said  to  be 
used. 

PREPARATION     OF     CELLULOID     ACCORDING    TO     TRIBOUILLET 
AND    BESANCELE. 

According  to  this  method,  which,  in  a  certain  sense,  ap- 
pears to  be  an  improvement  on  Hyatt's  process,  100  parts  of 
collodion-cotton  are  very  intimately  mixed  with  42  to  50 
parts  of  camphor.*  The  mass  is  then  wrapped  in  very  strong 
press-cloths,  and  brought  into  a  hot-press,  very  similar  in 
construction  to  that  used  in  candle  factories  for  pressing  oleic 
acid  from  crude  acid  cakes.  The  masses  to  be  pressed  lie 
between  hollow  iron  prisms  heated  by  steam,  and  by  means 
of  a  hydraulic  press  the  whole  is  pressed  together  to  the 
same  extent  as  the  press-cakes  become  thinner.  The  press 
is  enclosed  in  a  box,  and  the  latter  is  connected  by  means 
of  a  pipe  with  a  cooled  space  in  which  the  vapors  escaping 
from  the  hot  pressed  mass  are  condensed.  In  pressing  the 
mixture  of  collodion-cotton  and  camphor,  the  escaping 
vapors  can  only  consist  of  water  and  camphor,  and  the 
object  of  this  arrangement  seems  to  be  to  recover  the  cam- 
phor present  in  excess. 

*  Although  it  is  not  thus  stated,  mixture  is  probably  effected  in  a  wet  state 
in  a  hollander. 


CELLULOID.  269 

After  remaining  for  several  hours  in  the  press,  the  cakes 
are  brought  into  a  box  upon  the  bottom  of  which  stands  a 
vessel  containing  a  substance  having  great  affinity  for 
water — calcium  chloride  or  sulphuric  acid — and  the  air  in 
the  vessel  is  then  exhausted.  The  mass  is  thus  completely 
dried,  and  the  preparation  of  the  celluloid  finished.  Ac- 
cording to  the  present  state  of  the  industry,  all  the  processes 
for  the  production  of  celluloid  by  purely  mechanical  means 
may  be  designated  as  obsolete,  and,  in  all  probability,  they 
have  generally  been  abandoned.  Although  it  is  a  fact  that 
by  the  presence  of  the  camphor  the  nitro-cellulose  is  de- 
prived of  its  explosive  power,  it  cannot  be  denied  that  such 
is  the  case  only  when  the  mixture  is  sufficiently  intimate. 
However,  such  an  intimate  mixture  is  only  effected  towards 
the  final  stages  of  the  manufacturing  process,  and  up  to 
that  period  the  operation  is  by  no  means  free  from  danger,  if 
care  is  not  taken  that  the  mass  up  to  the  time  of  hot-press- 
ing contains  enough  water  to  render  explosion  impossible. 

PREPARATION  OF  CELLULOID  WITH  ALCOHOLIC  CAMPHOR 
SOLUTION. 

This  process  yields  good  results,  and  is  said  to  possess  the 
great  advantage  of  all  danger  of  explosion  being  excluded 
— which,  however,  may  be  doubted.  The  collodion-cotton 
is  prepared  by  grinding,  and  is  then  freed  as  far  as  possible 
from  water,  when  solution  of  camphor  in  strong  alcohol  is 
poured  over  it,  the  solution  being  brought  in  contact  with 
all  portions  of  the  collodion-cotton  by  vigorous  manipula- 
tion of  the  mass. 

The  mass  is  then  heated  in  a  closed  vessel  under 
pressure.  Alcohol  boiling  at  a  temperature  far  below  the 
boiling  point  of  water,  it  will  be  impossible  to  reach  in  such 
a  vessel  a  temperature  of  266°  F.,  at  which  the  formation 
of  celluloid  is  said  to  take  place.  Heating  should  probably 
not  be  carried  beyond  a  point  at  which  complete  solution 
of  the  collodion-cotton  in  the  alcoholic  camphor  solution  is 


270  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

effected.  While  collodion-cotton  does  not  dissolve  in  alco- 
hol at  the  ordinary  pressure,  solution  is  effected  by  heating 
it  together  with  alcohol  under  a  certain  pressure. 

When  solution  is  complete,  the  mass  is  allowed  to  remain 
in  the  closed  vessel  until  cooled  to  the  ordinary  tempera- 
ture. It  forms  a  gelatinous  substance  consisting  of  celluloid 
saturated  with  alcohol  and  water.  For  the  removal  of  the 
latter,  heat  cannot  be  applied  as  otherwise  the  surface  which 
solidifies  first  would  be  full  of  bubbles  caused  by  the  vapors 
being  unable  to  escape  through  the  viscous  mass.  Hence, 
in  order  to  obtain  a  uniform  product  free  from  bubbles,  the 
soft  celluloid  mass  will  have  to  be  cut  up  into  thin  slices, 
and  the  latter  dried  in  a  warm  room.  Drying  requires 
quite  a  long  time,  and  all  the  alcohol  used  is  lost.  When 
a  piece  not  thoroughly  dry  is  tested  with  a  knife,  the  out- 
side will  be  found  quite  solid  while  inside  it  is  of  a  lard- 
aceous  nature.  By  immersing  the  dry  pieces  in  hot  water, 
they  can  be  made  soft  and  plastic,  and  by  rolling  readily 
combined  to  a  homogeneous  mass. 

PREPARATION  OF  CELLULOID  ACCORDING  TO  MAGNUS. 

The  process  introduced  by  Magnus,  of  Berlin,  for  the  pre- 
paration of  celluloid  is  perhaps  the  most  rational  one  of  all 
the  wet  methods,  because  with  the  exercise  of  sufficient  care 
all  danger  of  explosion  or  fire  is  excluded. 

The  description  of  Magnus's  process,  which  has  become 
public,  is  also  very  meagre,  and  it  may  be  seen  at  the  first 
glance  that  it  contains  only  the  principle  of  the  entire  pro- 
cess, but  that  its  technical  execution  will  probably  have  to 
be  effected  in  a  less  simple  manner. 

According  to  law,  collodion-cotton  as  brought  into  com- 
merce must  contain  at  least  25  per  cent,  of  water,  the  possi- 
bility of  explosion  being  only  excluded  under  these  condi- 
tions. Now,  it  has  been  stated,  that  in  the  Magnus  factory, 
the  wet,  compressed  collodion-cotton  is  separated  and  dried 
upon  hot  iron  plates(I).  An  explosion  of  collodion-cotton 
thus  treated  could  in  all  probability  scarcely  be  avoided. 


CELLULOID.  271 

The  mode  of  preparing  the  solution  of  dry  collodion- 
cotton  is  as  follows :  Over  50  parts  by  weight  of  collodion- 
cotton  is  poured  a  mixture  of  100  parts  by  weight  of  ether 
and  5  parts  by  volume  of  alcohol  of  0.728  specific  gravity, 
28  parts  by  weight  of  camphor  having  been  previously  dis- 
solved in  this  mixture.  Stone-ware  pots  covered  with  a 
loaded  rubber  plate  are  used  for  dissolving  purposes.  The 
mass  is  from  time  to  time  stirred  till  solution  is  complete 
and  the  pots  contain  a  gelatinous  mass.  It  is  further  stated 
that  this  mass  becomes  plastic  after  some  time  by  manipu- 
lation between  rolls,  and  that  plates  may  be  prepared  from 
it  which  are  kept  till,  by  the  evaporation  of  the  greater  por- 
tion of  the  ether,  they  have  become  hard  enough  to  be 
pressed,  the  latter  operation  being  effected  in  hot  presses, 
and  the  quality  of  the  celluloid  is  said  to  be  the  better,  the 
more  sharply  the  plates  are  pressed. 


According  to  another  process  which  differs  but  little  from 
the  one  described  above,  in  place  of  ether,  methyl  alcohol 
in  which  the  required  quantity  of  camphor  has  been  dis- 
solved is  used  as  a  solvent  for  the  collodion-cotton. 

PREPARATION  OF  CELLULOID  WITH  RECOVERY  OF  THE 
SOLVENT. 

It  must  appear  strange  to  any  one  conversant  with  chem- 
ical principles,  how  incomplete  and,  in  certain  respects,  very 
singular,  are  the  descriptions  given  above  for  the  preparation 
of  celluloid.  It  is,  therefore,  considered  advisable  to  give 
here  a  description  of  a  process  which  can  be  practically  ap- 
plied, it  being  without  danger  and  allowing  of  the  recovery 
of  the  quite  expensive  solvents. 

With  reference  to  the  basis-material  of  the  entire  celluloid 
manufacture,  namely,  collodion-cotton,  it  may  be  said  that, 
while  it  could  probably  be  obtained  from  different  manu- 
facturers of  chemical  products,  it  would  be  preferable  to 
prepare  it  in  the  celluloid  plant  itself,  because  by  this  means 


272  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

a  product  would  be  obtained  which,  as  regards  complete  solu- 
bility, answers  all  demands.  In  a  larger  plant  producing 
annually  large  quantities  of  celluloid  articles,  the  prepara- 
tion of  collodion-cotton  in  the  plant  itself  would  also  appear 
advisable  from  an  economical  standpoint. 

In  describing  the  manufacture  of  artificial  silk  according 
to  Chardonnet's  method,  attention  has  been  drawn  to  the 
great  care  bestowed  upon  the  production  of  mtro-cellulose 
which  is  completely  soluble,  and  collodion-cotton  possessing 
this  property  being  also  required  for  the  manufacture  of 
celluloid,  the  reader  is  referred  to  the  process  used  by  Char- 
donnet.  When  a  freshly-prepared  quantity  of  collodion- 
cotton  is  to  be  worked,  it  is,  in  all  cases,  advisable  to  test  a 
sample  of  it  as  to  its  solubility.  For  this  purpose  a  small 
quantity  of  the  collodion-cotton  is  thoroughly  dried.  One 
gramme  (15.43  grains)  of  the  dry  mass  is  brought  into  a 
large  test-tube  and  200  cubic  centimeters  (12.2  cubic  inches) 
of  ether  are  poured  over  it.  Solution  is  hastened  by  con- 
tinued shaking,  and  the  test-tube  is  then  placed  perpen- 
dicularly in  a  place  protected  from  shocks. 

In  the  course  of  24  hours,  the  contents  of  the  test-tube 
should  form  a  clear,  transparent  fluid,  which  is  a  proof  of 
the  entire  quantity  of  collodion-cotton  having  been  dis- 
solved in  the  ether.  If  an  opalescent  layer  appears  on  the 
bottom  of  the  test-tube,  it  consists  of  nitre-cellulose  swollen 
up  but  not  dissolved.  The  quantity  of  this  can  be  readily 
determined  by  quickly  filtering  the  fluid,  washing  the 
residue  remaining  upon  the  filter  with  ether,  drying  and 
weighing  it.  By  deducting  the  weight  of  the  filter,  the 
quantity  of  nitro-cellulose  which  has  remained  undissolved 
is  found. 

It  may  here  be  remarked  that  perfectly  colorless  celluloid 
can  under  no  conditions  be  produced  from  incompletely- 
dissolved  collodion-cotton,  though  the  latter  may  be  used 
for  opaque  or  intensely  colored  celluloid  articles. 

Collodion-cotton  to   be  dissolved  must  be  perfectly  free 


CELLULOID.  273 

from  water.  The  wet  material  is  separated  as  far  as  pos- 
sible to  a  flocculent  mass  resembling  wadding  and,  after 
spreading  it  out  in  thin  layers  upon  metal  plates,  is  dried 
with  the  use  of  the  same  precautionary  measures  as  described 
in  detail  in  the  manufacture  of  nitro-cellulose. 

The  drying  plant  need  not  be  of  large  size,  and  it  should 
be  laid  down,  as  a  rule,  not  to  dry  more  collodion-cotton  at 
one  time  than  is  to  be  dissolved  the  same  day.  By  proceeding 
in  this  manner  all  danger  which  may  also  arise  from  en- 
tirely dry  collodion-cotton  is  excluded. 

The  apparatus  in  which  the  solution  of  the  collodion 
cotton  and  camphor  is  effected,  as  well  as  the  preparation 
of  the  fluid  celluloid,  consists  of  an  iron  cylinder  which  may 
be  constructed  of  ordinary  boiler-plate,  but  has  to  be  well 
tinned  inside.  The  head  of  the  cylinder  is  provided  with 
an  aperture,  which  can  be  closed  air-tight,  for  the  introduc- 
tion of  the  solid  materials,  while  on  one  of  the  sides  the 
cylinder  is  furnished  with  a  pipe  for  the  admission  of  the 
solvent.  Through  the  centre  of  the  head  of  the  cylinder 
passes  the  shaft  of  a  stirrer  which  carries  a  spiral  of  tinned 
sheet-iron.  The  bottom  of  the  cylinder  is  furnished  with  a 
discharge  pipe  for  the  finished  solution,  and  one  side  is 
fitted  with  a  small  cock  for  taking  samples  of  the  fluid. 

The  manner  of  working  with  this  apparatus  is  as  follows  : 
The  quantity  of  camphor  intended  for  the  operation  is  first 
introduced,  and  then  the  dry  collodion-cotton,  when  the 
cylinder  is  closed  and  the  stirrer  slowly  set  in  motion,  the 
solvent  being  at  the  same  time  admitted  through  the  side- 
pipe.  The  stirrer  is  uninterruptedly  kept  in  slow  motion, 
the  formation  of  masses  which  are  simply  swollen  and  im- 
pede solution  being  thereby  prevented.  The  stirrer  is  only 
stopped  when  it  is  shown  by  samples  taken  from  time  to 
time  that  solution  is  complete. 

As  regards  the  solvent  to  be  used  there  is,  in  our  opinion, 
but  one  which  is  actually  entirely  suitable,  namely,  pure 
anhydrous   ether.     Solution   of  the  collodion-cotton   may 
18 


274  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

possibly  be  hastened  by  mixtures  of  ether  and  alcohol,  it 
being  asserted  by  some  that  such  is  the  case,  but  they  ex- 
ert an  injurious  influence  in  working  the  celluloid  masses. 

Pure  ether  boils  at  96.8°  F.;  absolute  alcohol  at  172.4° 
F.,  and  the  small  quantity  of  water  contained  in  alcohol 
when  not  absolute,  only  at  212°  F.  When  the  finished 
solution  is  brought  in  contact  with  air,  the  ether  of  all  the 
fluids  present  will,  of  course,  evaporate  first,  so  that  after  a 
certain  time  the  mass  contains  almost  no  ether  whatever, 
but  nearly  the  entire  quantity  of  alcohol,  and  most  certainly 
all  the  water.  For  the  evaporation  of  the  alcohol  greater 
heat  will  have  to  be  used  and  the  alcoholic  vapors  evolved, 
and  later  on  the  aqueous  vapors  also,  will  form  in  the  mass, 
which  has  in  the  meantime  become  viscous,  bubbles  which 
cause  the  celluloid  plates  to  bulge  and  can  only  with  diffi- 
culty be  removed  by  rolling.  Hence  to  avoid  all  difficul- 
ties in  working,  dry  collodion-cotton  and  anhydrous  ether 
should  only  be  used. 

The  recovery  of  the  ether  evaporating  from  the  fluid 
celluloid  mass  has  generally  been  declared  impossible,  so 
that  it  is  simply  allowed  to  escape  in  the  form  of  vapor  into 
the  air.  This  procedure,  however,  has  many  disadvantages, 
the  cost  of  production  being,  on  the  one  hand,  increased, 
and  on  the  other,  it  leads  to  many  inconveniences  in  the 
manufacture  itself.  By  being  constantly  in  an  atmosphere 
impregnated  with  vapors  of  ether,  the  health  of  the  work- 
men is  likely  to  be  impaired,  and  in  factories  working  in 
this  manner,  the  workrooms  should  always  be  kept  thor- 
oughly aired.  Another  drawback  is  the  great  danger  from 
fire,  as  by  the  mere  striking  of  a  match,  the  mixture  of  air 
and  ether-vapor  might  be  ignited  and  cause  a  fearful 
explosion. 

RECOVERY  OF  THE  ETHER. 

By  working  according  to  the  method  described  below, 
almost  the  entire  quantity  of  ether  used  for  the  preparation 


CELLULOID.  275 

of  the  celluloid  solution  may  be  recovered,  the  cost  of  pro- 
duction thus  being  considerably  reduced.  The  odor  of 
ether  can  scarcely  be  noticed  in  the  factory,  and  there  is  no 
danger  from  fire,  and  injury  to  the  health  of  the  workmen 
is  excluded. 

An  apparatus  of  the  following  construction  is  used  :  The 
clear  solution  of  celluloid  mass  prepared  in  the  manner 
above  described,  is  brought  into  a  sheet-iron  cylinder  tinned 
inside,  and  provided  on  the  top  with  a  gutter  4  to  6  inches 
deep,  into  which  fits  the  rim  [of  the  lid.  In  the  latter  is 
fitted  a  small  cock,  and  above  the  bottom  of  the  cylinder  is 

FIG.  36. 


a  pipe  with  a  stop-cock,  which  serves'  for  the  discharge  of 
the  fluid.  The  solution  to  be  worked  is  introduced  through 
a  pipe  furnished  with  a. stop-cock,  which  enters  the  cylinder 
at  a  slight  distance  below  the  gutter.  The  latter  is  kept 
filled  with  water,  the  hydraulic  joint  thus  formed  prevent- 
ing the  escape  of  ether-vapor.  By  this  arrangement  the 
interior  of  the  cylinder  is  accessible  without  difficulty. 
When  the  cylinder  is  to  be  filled  with  solution,  the  small 
cock  fitted  in  the  lid  is  opened  to  allow  the  escape  of  air. 

For  the  purpose  of  solidifying  the  solution,  a  shallow  tray 
of  the  shape  shown  in  Fig.  36  is  used.     It  is  constructed  of 


276 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


tinned  sheet-iron  and  measures  39.37  inches  in  length  and 
width,  and  2.36  inches  in  depth.  It  is  divided  into  12  or 
15  compartments  by  partitions  1.18  inches  high,  so  that 
each  compartment  is  12.99  inches  long,  7.87  (or  9.84)  inches 
wide,  and  2.36  inches  deep. 

Ten  such  trays  W,  may  be  placed  one  above  the  other,  in 
the  ten  compartments  of  a  wooden  box  shown  in  section  in 
Fig.  37.  On  the  right  of  this  box  is  a  small  box  A,  com- 

FIG.  37. 


4;fc 


T\ 


K. 


J 


w 


W 


B 


w 


£ 


w 


JE 


W 


w 


w 


municating  below  with  the  pipe  R,  and  connected  by  means 
of  the  narrow  longitudinal  slits  o,  with  the  separate  com- 
partments in  which  the  trays  stand.  On  the  left  of  the 
box  is  another  small  box  B,  of  the  same  construction  as  A, 
and  connected  with  the  pipe  R. 

The  pipe  Rl  communicates  with  the  apparatus  for  con- 
densing the  ether-vapors,  its  arrangement  being  shown  in 
Fig.  38.  The  pipe  Rl  terminates  in  a  long,  wide  tin  coil  S, 
lying  in  a  vat  kept  constantly  full  of  cold  water.  The 
lower  end  of  the  coil  passes  into  the  neck  of  a  large  flask  F, 
fitted  near  the  bottom  with  a  cock  through  which  the 
condensed  ether  is  drawn  off.  A  narrower  pipe  St  made 


CELLULOID. 


277 


into  a  coil  in  a  vessel  filled  with  ice  and  passing  out  free, 
branches  off  from  the  neck  of  the  flask  F. 

The  operation  of  preparing  solid  celluloid  with  this  ap- 
paratus is  as  follows :  One  of  the  trays  W,  is  rilled  up  to  a 
mark  1.97  inches  above  its  bottom  with  solution  from  the 
cylinder,  and  placed  in  the  uppermost  compartment  of  the 
box.  The  other  trays  having  in  the  same  manner  been 
filled  with  solution  are  then  successively  placed  in  the  com- 

FJG.  38. 


partments  of  the  box,  and  the  door  of  the  latter  is  closed 
air-tight. 

By  means  of  a  small  ventilator,  a  constant  current  of 
warm  air  is  slowly  conducted  through  the  pipe  R,  into  the 
box.  This  current  of  air  is  produced  as  follows :  In  a  room 
underneath  the  workroom,  and  entirely  isolated  from  it,  a 
boiler  is  bricked  in  an  ordinary  fire-place.  In  this  boiler, 
which  is  filled  with  water,  lies  a  tin  coil  open  on  one  end 
and  connected  on  the  other,  with  the  ventilator  which  com- 


278  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

municates  with  the  pipe  R,  extending  through  the  floor  of 
the  workroom.  When  the  water  in  the  boiler  has  been 
brought  to  the  boiling-point,  the  air  in  the  coil  becomes 
heated,  is  sucked  off  by  the  ventilator,  and  replaced  by 
fresh  air  flowing  in,  so  that  there  is  constantly  a  current  of 
warm  air  in  the  pipe  R.  The  course  of  the  operation  is  so 
regulated  that  the  current  of  air  moves  slowly,  and  that  its 
temperature  never  exceeds  86°  to  89.6°  F.  Ether  boils  at 
96.8°  F.,  and  should  the  temperature  of  the  air  become  that 
high,  the  mass  in  the  trays  might  be  brought  to  the  boiling 
point  and  in  solidifying  be  interspersed  with  bubbles.  The 
current  of  warm  air  enters  through  the  narrow  slits  o,  by 
means  of  which  the  box  A  is  connected  with  the  compart- 
ments in  which  the  trays  stand,  and  in  passing  to  and  fro 
over  the  surface  of  the  fluid,  becomes  impregnated  with  the 
vapors  of  the  ether.  It  then  enters  the  box  B,  and  passes 
through  the  pipe  R1  into  the  coil  St  which  is  surrounded  by 
cold  water.  The  greater  portion  of  the  ether  contained  in 
the  air  condenses  to  fluid  and  collects  in  the  flask  F,  from 
which  it  is  from  time  to  time  drawn  off.  The  air  escaping 
from  Ft  can  only  pass  out  through  the  coil  St  which  ter- 
minates outside  the  workroom.  The  coil  Sl  lying  in  the 
vessel  filled  with  ice,  the  last  traces  of  ether  are  condensed 
and  run  back  into  the  flask  F. 

With  the  use  of  these  contrivances,  the  evaporation  of 
the  ether  in  the  celluloid  solution  is  very  rapidly  effected, 
and  the  contents  of  the  trays  are  gradually  converted  into 
a  mass  somewhat  resembling  congealing  glue.  The  depth 
of  the  layer  of  fluid  in  the  tray,  which  was  originally  1.97 
inches,  having  been  constantly  reduced  by  the  evaporation 
of  ether,  and  the  height  of  the  partitions  being  but  1.18 
inches,  each  compartment,  when  evaporation  has  progressed 
to  a  certain  degree,  will  contain  a  body  representing,  when 
the  mass  has  become  perfectly  dry,  a  prism  12.99  inches 
long,  7.87  inches  wide,  and  about  0.98  inch  thick.  When 
drying  is  finished,  each  of  these  prisms  may  be  obtained  by 


CELLULOID.  279 

itself  by  turning  the  tray  upside  down,  and  the  dimensions 
of  these  prisms  are  just  right  to  allow  of  their  being  con- 
veniently worked  with  suitable  rolls.  Drying  of  the  cellu- 
loid mass  may  be  considered  complete,  when  a  sample 
prism  taken  from  one  of  the  trays  can  be  cut  like  quite 
solid  cheese. 

THE    DRYING    CHAMBER. 

The  prisms  taken  from  the  trays  are  placed  in  a  drying 
chamber  heated  by  warm  air  and  provided  with  a  pipe  ter- 
minating either  in  the  open  air  or  in  a  chimney.  The 
temperature  of  the  chamber  may  be  104°  to  113°  F.,  the 
last  traces  of  ether  still  adhering  to  the  mass  being  thereby 
evaporated.  The  drying  chamber  is  furnished  with  frames 
covered  with  nets  of  stout  twine  upon  which  the  prisms  are 
placed  so  that  they  rest  upon  one  of  their  narrow  longi- 
tudinal sides.  They  remain  in  the  drying  chamber  till 
they  form  a  hard,  horn- like  mass,  and  the  fracture  of  a 
broken  piece  presents  a  perfectly  uniform  appearance,  a 
lardaceous  appearance  of  the  fracture  being  indicative  of 
insufficient  drying. 

If  the  crude  celluloid  is  to  be  rolled,  it  has  to  be  heated 
to  acquire  sufficient  plasticity,  and  the  drying  chamber  may 
also  be  used  for  this  purpose.  When  drying  is  finished  a 
current  of  air  having  a  temperature  of  140°  to  158°  F.  is 
conducted  into  the  chamber,  this  temperature  sufficing  to 
give  to  the  celluloid  the  required  softness.  One  plate  after 
the  other  may  then  be  taken  from  the  chamber  and  passed 
through  the  rolls. 

The  preparation  of  celluloid  with  the  assistance  of  the 
contrivances  described  above,  presents  many  material  ad- 
vantages, it  being  possible  to  prepare  in  a  short  time  in  a 
small  room  larger  quantities  of  celluloid,  and  recover  almost 
the  entire  quantity  of  ether  required  for  making  the  solu- 
tion. The  workmen  are  not  exposed  to  the  vapors  of  ether, 
and  there  is  no  danger  from  fire  during  the  entire  operation. 


280  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

The  plates  of  crude  celluloid  obtained  by  the  above- 
described  method  are  either  entirely  colorless  or  of  a  slightly 
yellowish  color.  However,  even  if  they  show  the  latter 
color,  they  should  be  perfectly  uniform  throughout  their 
entire  bulk,  dull  and  cloudy  spots  imbedded  in  the  trans- 
parent mass  being  indicative  of  the  solution  used  having 
contained  particles  of  nitro-cellulose  only  swollen  but  not 
dissolved.  As  previously  mentioned,  such  defective  cellu- 
loid may  be  used  for  the  preparation  of  masses  which  are  to 
be  colored,  or  filled.  Dull  spots  may  sometimes  disappear 
by  long-continued  rolling. 

The  dried  material  does  not  yet  possess  the  great  hard- 
ness and  elasticity  characteristic  of  celluloid,  it  acquiring 
these  properties  only  by  mechanical  manipulation,  the  first 
step  being  rolling,  and  the  more  frequently  this  operation 
is  repeated  and  the  greater  the  pressure  applied,  the  better 
the  quality  of  the  product  will  be.  It  would  therefore  seem 
that  by  this  purely  mechanical  process,  a  change  in  the 
position  of  the  finest  particles  of  the  celluloid  is  effected. 

PROPERTIES  OF  CELLULOID. 

Celluloid  prepared  in  a  proper  manner  forms,  as  pre- 
viously mentioned,  a  colorless  or  very  slightly  yellow  mass 
closely  resembling  horn,  or  still  more  so,  tortoise  shell.  It 
represents  a  mass  with  a  slight  odor  of  camphor,  becoming, 
however,  in  the  course  of  time  entirely  odorless  by  reason 
of  the  evaporation  of  the  particles  of  camphor  lying  near 
its  surface.  By  vigorously  rubbing  or  heating  an  article  of 
celluloid,  the  odor  of  camphor  becomes  more  pronounced. 

At  the  ordinary  temperature,  rolled  celluloid  is  very  hard 
and  extraordinarily  elastic,  arid  thicker  pieces  of  it  can 
scarcely  be  broken.  It  may  be  sawed,  planed  and  turned 
in  the  lathe  like  fine-grained  wood.  A  thin  plate  of  it  may 
be  cut  with  the  scissors,  it  behaving  in  this  respect,  some- 
what like  very  solid  cardboard. 

Celluloid,  firm  and  brittle  as  it  is  at  the  ordinary  tern- 


CELLULOID.  281 

perature,  may  b}^  suitable  heating  be  changed  into  a  very 
plastic  mass  which  can  be  moulded  into  any  desired  shape. 

Celluloid  being  a  bad  conductor  of  heat,  larger  pieces  of 
it  to  be  rendered  plastic  have  to  be  for  a  longer  time  ex- 
posed to  an  adequate  heat,  otherwise  they  would  offer  too 
much  resistance  in  rolling  or  pressing.  Celluloid  becoming 
quite  plastic  at  a  temperature  of  158°  F.,  pieces  of  it  are 
most  conveniently  worked  by  throwing  them  in  a  vessel 
full  of  boiling  water,  covering  the  vessel,  and  allowing  the 
whole  to  stand  quietly  for  some  time,  when  by  samples 
taken  from  the  vessel  it  is  ascertained  whether  the  pieces 
are  sufficiently  plastic. 

The  plasticity  of  celluloid  increases  considerably  at  a 
higher  temperature.  When  heated  to  between  248°  and 
302°  F.,  it  is  as  plastic  as  wax,  and  like  it,  can  be  given 
any  shape  desired  by  pressing  it  in  a  mould,  or  two  pieces 
of  the  hot  mass  ma}r  be  made  into  one  by  pressure. 

If  heating  the  cellulose  be  effected  so  that  the  rise  in  the 
temperature  can  be  accurately  determined,  it  will  be  noticed 
that  up  to  nearly  284°  F.  no  other  change  takes  place 
besides  greater  softness  and  plasticity.  If,  however,  the 
temperature  be  increased  to  284°  F.,  a  molecular  change 
takes  place ;  the  mass  suddenly  becomes  opaque,  and  by 
slightly  raising  the  temperature,  at  the  utmost  to  293°  F., 
spontaneous  decomposition  sets  in.  The  mass  puffs  up  very 
much  and  decomposes,  a  heavy  smoke  being  evolved. 
However,  there  is  no  explosion,  this  being  a  proof  that  the 
celluloid  no  longer  contains  nitro-cellulose. 

On  coming  in  contact  with  a  burning  body,  celluloid 
ignites  very  readily,  and  burns  with  a  yellow,  luminous, 
sooty  flame,  the  odor  of  camphor,  caused  by  the  evaporation 
of  this  substance  being  very  pronounced.  When  the  flame 
of  the  burning  celluloid  is  blown  out,  combustion  continues 
very  rapidly  without  flame,  vapors  of  camphor  ascending 
constantly  from  the  glowing  mass.  The  process  which 
thereby  takes  place  consists  in  that  the  nitro-cellulose,  by 


282  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

reason  of  its  high  content  of  oxygen,  continues  to  burn,  and 
the  camphor  evaporates  in  consequence  of  the  heat  devel- 
oped, the  temperature  being,  however,  not  sufficiently  high 
for  the  ignition  of  the  camphor  vapors. 

Towards  solvents,  celluloid  behaves  quite  indifferently. 
In  water  it  remains  entirely  unchanged  and,  by  reason  of 
this  property,  it  is  used  for  making  syringes,  basins,  etc., 
for  surgical  purposes.  When  placed  for  some  time  in  strong 
alcohol,  it  swells  up  very  much,  but  does  not  dissolve,  solu- 
tion being  gradually  effected  only  by  the  addition  of  ether. 
By  being  allowed  to  stand  in  the  air,  the  solution  yields 
celluloid  with  its  original  properties.  When  left  for  a 
longer  time  in  contact  with  sulphuric  acid,  it  is  completely 
dissolved,  and  concentrated  nitric  acid  dissolves  it  without 
residue.  By  concentrated  soda  lye  it  is  only  dissolved  when 
remaining  for  a  longer  time  in  contact  with  it. 

The  physical  properties  of  celluloid  are  the  same  as  those 
of  horn,  wood  and  wax.  In  mechanical  manipulations 
such  as  cutting,  sawing,  planing,  turning,  it  can  be  treated 
just  like  horn  or  wood,  and  in  fact  behaves  to  better  ad- 
vantage for  the  operator  as,  being  a  structureless  substance, 
it  can  in  the  same  manner  be  worked  in  every  direction. 
Like  wax,  it  possesses  the  property  of  being  by  heat  con- 
verted into  a  very  plastic  substance  which  can  readily  be 
brought  into  any  desired  form.  It  commences  to  become 
plastic  at  about  122°  F.,  and  plates  of  it  heated  to  this  tem- 
perature may  be  rolled  under  strong  pressure.  At  a  higher 
temperature  its  plasticity  increases  considerably  and,  as  a 
rule,  one  of  212°  F.  suffices  for  all  kinds  of  operations  by 
rolling  or  pressing.  At  248°  F.  it  becomes  soft  enough  to 
allow  of  two  pieces  being  made  into  one  by  kneading. 

One  of  the  most  prominent  properties  of  celluloid  is  its 
great  tenacity  combined  with  uncommonly  great  elasticity. 
A  stick  of  it  as  thick  as  a  finger  can  at  the  ordinary  tem- 
perature be  bent  to  and  fro,  regaining  its  original  form 
when  the  tension  ceases :  no  flaws  or  cracks  are  formed 


OF  THE 

UNIVERSITY, 

OF 


CELLULOID.  283 


even  by  frequently  repeated  bending,  and  such  a  stick  can 
scarcely  be  broken.  However,  when  exposed  to  a  very  low 
temperature  celluloid  has  a  tendency  to  become  brittle. 

WORKING    CELLULOID. 

The  masses  obtained  by  completely  drying  the  pieces  and 
by  evaporating  celluloid  solutions,  do  not  show  the  great 
hardness,  elasticity  and  high  lustre  possessed  by  articles  pre- 
pared from  them,  but  are  of  a  more  or  less  soft  nature,  hav- 
ing in  this  respect  a  certain  resemblance  to  not  entirely 
dried  gelatine.  These  properties  appear  only  by  vigorous 
mechanical  manipulation,  a  change  in  the  position  of  the 
smallest  particles  of  the  mass  being  probably  effected,  or 
they  are  more  closely  drawn  together  than  is  the  case  in 
the  mass  when  simply  dried. 

The  mechanical  manipulation  of  celluloid  should  always 
commence  with  rolling  the  plates.  For  this  purpose,  the 
sufficiently  dried  plates  are  heated  in  the  drying  chamber 
to  between  140°  and  158°  F.,  and  thrown  into  hot  water 
where  they  are  allowed  to  remain  till  heated  throughout. 
It  is  of  great  importance  that  the  plates  should  be  heated 
throughout  their  entire  thickness,  as  otherwise  they  would 
tear  laterally  under  the  rolls. 

For  the  purpose  of  rolling,  smooth  steel  rolls,  so  arranged 
that  the  distance  between  them  can  be  regulated  at  will, 
are  used.  In  order  to  be  able  to  carry  on  the  work  rapidly, 
it  is  advisable  to  place  several  such  pairs  of  rolls  one  behind 
the  other,  the  rolls  of  each  succeeding  pair  being  more 
closely  set  than  those  of  the  preceding  one,  so  that  the  plate 
which  has  been  drawn  out  in  the  first  pair  of  rolls  is  rapidly 
converted  into  a  very  thin  plate.  By  working  in  this  man- 
ner, the  plate  heed  only  to  be  heated  once,  enough  heat  to 
keep  it  sufficiently  soft  being  developed  by  the  pressure. 

The  thin  plates  thus  obtained  are  placed  together  and 
are  sufficiently  heated  to  allow  of  their  being  welded  to- 
gether when  rolling  is  repeated.  The  more  frequently  roll- 


284  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

ing  is  repeated  and  the  greater  the  pressure,  the  more 
tenacious,  elastic  and  lustrous  the  celluloid  will  be.  Ac- 
cording to  the  purpose  to  which  the  celluloid  is  to  be 
applied,  thinner  or  thicker  plates  of  it  are  prepared  by 
rolling.  For  further  working  these  plates  are  sufficiently 
heated,  and  articles  prepared  from  them,  as  a  rule,  by 
stamping  or  pressing  in  warmed  hollow  moulds. 

COLORING    CELLULOID. 

Like  artificial  silk,  celluloid  possesses  the  property  of 
being  readily  colored,  it  taking  up  with  special  facility  the 
soluble  tar  colors.  If  an  article  of  colorless  celluloid  be 
only  for  a  short  time  placed  in  the  solution  of  a  dye- 
stuff,  the  surface  only  will  be  colored,  the  interior  remain- 
ing colorless,  but  if  left  in  it  for  a  sufficiently  long  time,  it 
will  be  colored  throughout  its  entire  mass.  Even  compara- 
tively thick  articles  appear  uniformly  colored  upon  their 
cross  sections  if  left  long  enough  in  the  solution.  It  may, 
therefore,  be  supposed  that  solutions  of  dye-stuff  penetrate 
the  celluloid  mass  like  a  sponge,  and  that  the  separate 
particles  of  the  coloring  matter  are  held  by  the  smallest 
particles  of  the  celluloid  mass. 

As  there  are  soluble  tar-colors  of  all  shades,  any  desired 
color  may  be  given  to  celluloid,  and  the  resulting  product 
is  distinguished  by  being  perfectly  transparent,  very  lustrous 
and  smooth,  surpassing  in  this  respect  the  finest  quality  of 
colored  gelatine. 

Transparent  celluloid  articles  are,  as  a  rule,  colored  a 
beautiful  golden  yellow,  which  is  readily  produced  by  plac- 
ing them  in  picric  acid  solution. 

Celluloid  of  any  desired  color  may  be  readily  obtained, 
and  there  are  several  ways  of  producing  articles  from  the 
colored  material.  The  most  simple  way  is  to  color  the 
celluloid  while  it  is  being  prepared.  This  is  effected  by 
mixing  with  the  celluloid  solution  when  finished,  coloring 
matter  soluble  in  alcohol,  the  solution  being  by  vigorous 


CELLULOID.  285 

stirring  distributed  throughout  the  fluid  in  order  to  obtain 
a  uniformly  colored  product.  A  certain  quantity  of  cellu- 
loid of  the  same  uniform  color  is  thus  obtained.  However, 
as  celluloid  of  different  colors  has  to  be  used  for  various 
purposes,  this  method  of  direct  coloring  while  preparing 
the  mass,  notwithstanding  its  convenience,  is  only  em- 
ployed in  exceptional  cases,  it  being  preferred  to  color  the 
finished  articles. 

The  simplest  plan,  as  previously  mentioned,  is  to  use 
tar-colors  soluble  in  alcohol,  they  being  readily  taken  up 
by  the  celluloid,  and  it  is  only  necessary  to  allow  the 
articles  to  remain  in  the  solution  till  they  are  sufficiently 
colored.  They  are  then  taken  out,  rinsed  in  water,  and 
made  lustrous  by  vigorous  rubbing  with  a  soft  cloth. 

However,  there  is  a  way  of  producing  certain  color  effects 
more  beautiful  than  can  be  done  with  tar  colors,  and  below 
a  few  hints  regarding  this  manner  of  coloring  are  given.  In 
this  operation  it  has  to  be  borne  in  mind  that  the  coloration 
depends  on  the  concentration  of  the  solutions  used ;  the 
more  saturated  they  are,  the  deeper  the  coloration  will  be. 
It  is  advisable  to  learn  by  a  few  small  experiments  the  re- 
quired concentration  of  the  solutions  to  be  used.  A  beauti- 
ful yellow  may  be  produced  by  placing  the  article  first  in 
solution  of  acetate  of  lead  in  water,  then  slightly  rinsing  it 
in  clean  water,  and  finally  bringing  it  into  a  solution  of 
potassium  dichromate  to  which  sufficient  soda  has  been 
added  to  color  it  yellow.  By  this  means  the  beautiful 
yellow  combination  known  as  chrome  yellow  is  formed  in 
the  pores  of  the  celluloid. 

Red  may  be  produced  in  various  ways.  A  very  beautiful 
scarlet  is  obtained  by  placing  the  articles  for  a  short  time 
in  water  which  has  been  compounded  with  a  small  quan- 
tity of  nitric  acid,  and  then  bringing  them  into  a  fluid  ob- 
tained by  treating  finely-powdered  cochineal  with  ammonia. 
When  the  desired  shade  of  color  has  been  attained,  the 
articles  are  taken  from  the  solution,  and  thoroughly  rinsed 


286  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

in  water.  A  dark,  peculiar  red  is  obtained  by  treating  the 
articles  first  with  a  solution  of  potassium  chromate,  and  then 
with  a  solution  of  nitrate  of  silver,  the  beautiful  red  silver 
chromate  being  thereby  formed.  A  magnificent  purple-red 
is  obtained  by  placing  the  articles  in  a  highly  dilute  solu- 
tion of  trichloride  of  gold,  and  then  exposing  them  to  the 
direct  sun  light.  By  the  action  of  the  latter  the  chloride  of 
gold  is  decomposed  and  the  celluloid  colored. 

Blue  may  also  be  obtained  by  various  means.  Indigo- 
blue  is  produced  by  simply  placing  the  celluloid  in  dilute 
solution  of  indigo-carmine  in  water.  Another  very  beauti- 
ful blue,  the  so-called  Berlin-blue,  is  obtained  by  placing  the 
articles  in  a  solution  of  ferric  chloride  in  water,  rinsing,  and 
bringing  them  into  a  solution  of  yellow  prussiate  of  potash. 

Green  is  obtained  by  placing  the  celluloid  in  a  solution 
prepared  from  2  parts  of  verdigris  and  1  part  of  ammonium 
chloride. 

Violet  may  be  produced  by  first  dyeing  the  articles 
slightly  blue  with  indigo,  and  then  treating  them  with 
cochineal  solution  till  the  desired  shade  of  violet  appears. 

Brown.  Prepare  a  solution  of  permanganate  of  potash  in 
water,  add  to  it  soda  solution  so  that  no  precipitate  is 
formed,  and  place  the  articles  in  the  fluid. 

Gray.  Silver-gray  is  obtained  by  placing  the  articles  in 
a  very  dilute  solution  of  acetate  of  lead,  and  then  bringing 
them  into  an  atmosphere  of  sulphuretted  hydrogen.  The 
lead  sulphide  formed  shows  a  peculiar,  metallic,  lustrous, 
gray  color.  It  is,  however,  absolutely  necessary  to  use,  as 
above  mentioned,  a  very  dilute  solution  of  acetate  of  lead, 
otherwise  the  color  will  be  black  instead  of  gray. 

Black.  Mix  solution  of  logwood  extract  with  solution  of 
tannin  in  water  and  allow  the  articles  to  remain  fa  the 
mixture  for  a  few  hours.  They  are  then  rinsed  in  water  and 
placed  in  ferrous  sulphate  (green  vitriol)  solution  whereby 
they  acquire  a  deep  black  color.  Another  metallic,  lustrous 
black  is  obtained  by  placing  the  articles  in  nitrate  of  silver 


CELLULOID.  287 

solution  ;  according  to  the  concentration  of  the  solution  the 
color  will  be  gray  to  deep  black. 

PRINTING    ON    CELLULOID. 

By  reason  of  its  smooth  surface,  ordinary  printing  inks 
do  not  adhere  well  to  celluloid  and,  without  special  treat- 
ment, it  would  be  impossible  to  print  on  it  in  colors. 

To  make  a  celluloid  plate  suitable  for  being  printed  on, 
its  surface  has  to  be  provided  with  a  fine  graining  in  a 
manner  similar  to  that  in  which  a  lithographic  stone  is 
prepared.  Celluloid  possessing,  however,  a  comparatively 
slight  degree  of  hardness,  graining  is  effected  by  means  of 
a  small  sand  blast,  the  originally  lustrous  plate  becom- 
ing thereby  matt.  The  plate  is  then  well  washed  with 
water  to  remove  all  the  celluloid  dust,  and  is  then  thor- 
oughly dried.  It  is  next  coated  with  a  varnish  consisting 
of  equal  parts  of  a  fine  quality  of  pale  linseed-oil  varnish 
and  colorless  copal  varnish  diluted  with  enough  oil  of  tur- 
pentine so  that  the  varnish  can  spread,  like  collodion,  over 
the  plate.  The  plate  is  coated  with  this  varnish  in  exactly 
the  same  manner  as  a  glass  plate  with  collodion  for  photo- 
graphic purposes.  The  excess  of  varnish  is  allowed  to  run 
back  into  the  flask,  and  the  plate  is  set  on  edge  to  dry. 

A  plate  thus  prepared  can  be  printed  on  in  the  press  in 
various  colors,  the  latter  adhering  as  well  as  on  paper.  If, 
after  the  colors  are  dry,  the  plate  is  coated  with  a  thick  cel- 
luloid solution  and  the  latter,  when  congealed,  is  polished 
with  a  soft,  woolen  stuff,  the  printing  ink  lies  under  a  layer 
of  celluloid,  and  the  plate  may  be  cleansed  without  fear  of 
effacing  the  printing. 

Celluloid  articles  may  also  be  provided  with  pictures  of 
various  colors  by  means  of  a  process  closely  resembling  that 
employed  for  the  production  of  the  so-called  transfer  pictures 
or  metachromatypes.  According  to  this  process  the  pictures 
are  in  inverted  succession  printed  in  colors  on  thin  paper, 
and  the  finished  impression  is  finally  coated  with  a  mass 


288  CELLULOSE,  AND    CELLULOSE    PKODUCTS. 

which  by  moistening  becomes  very  sticky.  In  transferring 
the  pictures  to  glass,  wood,  porcelain,  etc.,  this  coating  is 
moistened,  and  the  paper,  coated  side  down,  is  laid  upon  the 
article  to  which  it  is  to  be  transferred,  and  firmly  pressed 
against  it.  After  a  short  time  the  paper  is  softened  by 
moistening  the  back,  and  is  then  carefully  drawn  off,  start- 
ing from  one  point.  The  paper  peels  off  smoothly  from  the 
picture,  the  latter  remaining  attached  to  the  basis. 

If  this  process  is  to  be  applied  to  the  ornamentation  of 
celluloid  articles,  the  colors  used  for  the  production  of  the 
picture  have  to  be  mixed  with  a  body  readily  soluble  in 
strong  alcohol,  soft  copal  finely  pulverized  being  a  suitable 
material  for  this  purpose.  When  all  the  colors  have  been 
printed,  the  printed  portions  of  the  paper  receive  an  addi- 
tional impression  made  with  spirit  copal  varnish,  the  rest 
of  the  paper  remaining  free. 

For  the  purpose  of  transferring  such  a  transfer  picture  to 
celluloid,  the  surface  of  the  latter  is  moistened  with  strong 
alcohol,  which  causes  the  uppermost  layers  of  the  celluloid 
to  swell  up,  and  the  paper,  picture  side  down,  is  laid  upon 
the  plate  thus  prepared.  The  latter  is  then  covered  with  a 
glass  plate  and  the  whole  placed  in  a  press  where  it  remains 
for  a  few  hours  under  slight  pressure.  When  there  can  be 
no  doubt  of  the  transferred  picture  adhering  firmly  and 
having  become  dry  by  the  evaporation  of  the  alcohol,  the 
plate  may  be  laid  in  water,  and  the  paper,  when  sufficiently 
softened,  carefully  drawn  off  from  the  picture. 

For  the  protection  of  the  picture  and  to  make  it  at  the 
same  time  durable,  it  may  be  coated  with  a  layer  of  cellu- 
loid by  pouring  celluloid  solution  over  it.  If  imitation 
gold  or  silver  has  been  used  in  printing  the  pictures,  this 
coating  with  celluloid  is  of  special  importance,  because 
these  materials,  when  exposed  to  the  air  soon  loose  their 
metallic  lustre,  and  the  pictures  become  unsightly.  If, 
however,  the  pictures  when  just  finished  are  provided  with 
a  layer  of  celluloid,  no  matter  how  thin,  the  colors  are  en- 


CELLULOID.  289 

tirely  excluded  from  the  action  of  the  air  and  retain  their 
metallic  lustre. 

Printing  on  celluloid  in  the  same  manner  as  pictures  in 
many  colors  are  produced  on  paper,  has  also  been  recently 
successfully  accomplished  by  the  use  of  tar  colors  soluble  in 
concentrated  acetic  acid,  the  colors  adhering  firmly  and 
retaining  their  sharp  outlines  without  running  into  each 
other.  These  colors,  as  shown  by  microscopical  examina- 
tion, strongly  attack  the  celluloid,  penetrating  to  a  great 
depth,  in  consequence  of  which  they  adhere  firmly.  How- 
ever, as  metals  are  also  attacked  with  great  energy  by 
acetic  acid,  metallic  printing  blocks  cannot  be  used  in  this 
case,  and  blocks  of  a  material  entirely  indifferent  towards 
acetic  acid  have  to  be  substituted  for  them,  gutta-percha 
being  especially  suitable  for  this  purpose.  Such  printing 
blocks  can  be  readily  made  by  taking  a  plaster  of  Paris 
cast  from  the  original — an  engraved  metal  plate,  or  a  wood- 
cut— laying  upon  it,  a  gutta-percha  plate  previously  softened 
in  hot  water,  and  subjecting  the  mould  together  with  the 
gutta-percha  plate  to  pressure  in  a  press  till  the  gutta-percha 
has  again  become  hard.  The  plate  then  shows  all  the  de- 
pressions and  elevations  of  the  original  plate,  and  may  at 
once  be  used  for  printing. 

CELLULOID    WITH    FILLING    MATERIALS. 

Celluloid  can  without  difficulty  be  worked  with  indiffer- 
ent bodies  into  uniform  masses,  the  substances  thus  ob- 
tained possessing,  in  addition  to  the  hardness  and  elasticity 
of  celluloid,  other  properties  which  make  them  suitable  for 
the  preparation  of  various  specialties. 

Although  all  kinds  of  perfectly  dry  substances  in  a  pul- 
verulent form  may  be  used  as  filling  material,  white  pul- 
verulent bodies  are,  as  a  rule  employed,  the  resulting  masses 
being  of  course  opaque. 

However,  since  so-called  white  bodies  are  colorless  and 
the  effect  appearing  as  white  to  the  eye  is  simply  due  to  the 
19 


290  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

peculiar  reflection  of  the  light,  masses  presenting  a  very 
characteristic  appearance  may  be  prepared  from  these  bodies 
and  from  celluloid. 

By  mixing  with  the  colorless  celluloid  only  a  small  quan- 
tity of  the  powder  of  a  white  body,  masses  are  obtained 
which,  though  appearing  white,  are  to  a  certain  degree 
transparent.  Milk  poor  in  fat  presenting  the  same  appear- 
ance. Masses  of  this  kind  are  called  milk-white,  and  articles 
of  a  beautiful  milk-white  color  may  be  made  from  celluloid. 
Ivory  also  appears  translucent,  but  its  color  is  not  pure 
white,  it  always  showing  a  yellowish  tinge.  Now,  there  is 
no  difficulty  whatever  in  mixing  a  white  pulverulent  body 
in  suitable  quantity  with  a  yellow  one,  and  by  combining 
this  mixture  with  celluloid,  masses  are  obtained  which,  as 
regards  color,  bear  a  close  resemblance  to  ivory. 

If  colorless  celluloid  be  mixed  with  a  suitable  quantity  of 
a  pure  white  body,  masses  resembling  in  appearance  polished 
white  marble  are  obtained.  By  the  addition  of  powders  of 
a  different  shade,  the  color  of  such  masses  may  be  toned 
down  as  much  as  desired. 

The  following  materials  may  be  used:  Magnesia,  chalk, 
talcum  or  starch.  For  certain  masses  which  are  to  be  very 
heavy,  artificially  prepared  barium  sulphate  (permanent 
white),  or  zinc  white  may  be  employed. 

Celluloid  masses  of  light  weight  being  especially  desirable 
for  the  manufacture  of  cane  heads,  etc.,  a  white  powder  of 
slight  specific  gravity  is,  as  a  rule,  used  as  filling  material, 
magnesium  powder  deserving,  in  this  respect,  preference 
above  all  others. 

The  filling  material  may  be  combined  with  the  celluloid 
either  in  the  preparation  of  the  latter  itself,  or  by  working 
it  into  the  finished  product. 

In  working  according  to  the  first  method,  the  mixture  of 
the  viscous  celluloid  solution  with  the  powder  is  best  effected 
in  a  contrivance  resembling  in  its  construction  a  revolving 
barrel,  it  consisting  of  a  tinned  sheet-iron  cylinder  revolv- 


CELLULOID.  291 


ing  around  its  axis.  The  quantity  of  the  solid  body  to  be 
used  having  been  introduced,  the  celluloid  solution  is  al- 
lowed to  run  in,  and  the  cylinder  closed  air-tight.  The 
cylinder  should  at  the  utmost  be  filled  three-quarters  full. 
It  is  then  slowly  revolved  by  means  of  a  mechanical  con- 
trivance, the  operation  being  continued  till  the  fluid  has 
combined  with  the  powder  to  a  viscous  mass  of  the  appear- 
ance of  cream. 

This  fluid  is  discharged  into  the  vessels  in  which  it  is  to 
coagulate  and  the  mass,  when  solidified,  is  thoroughly  dried, 
the  product  obtained  being  white  celluloid  plates.  In  cut- 
ting such  a  plate  in  two,  it  will  frequently  be  observed  that 
the  portion  of  it  which  had  been  in  contact  with  the  bottom 
of  the  coagulating  vessel  is  pure  white,  while  the  opposite 
portion  is  milk-white,  this  being  readily  explained  by  a 
portion  of  the  powder  having  subsided  in  the  fluid  while  at 
rest.  This  is,  however,  of  no  consequence,  the  coloration 
becoming  uniform  by  itself,  if  in  the  subsequent  rolling  of 
the  mass  the  thin  plates  are  put  together,  and  again  rolled. 

The  other  method  for  combining  the  pulverulent  filling 
substance  with  the  celluloid,  consists  in  uniformly  scattering 
the  powder  upon  the  celluloid  plates  previously  softened, 
and  rolling  them  repeatedly  till  the  color  is  uniform 
throughout. 

Celluloid  masses  combined  with  a  filling  substance  may 
also  be  colored,  and  articles  of  very  handsome  appearance 
made  from  them.  Special  mention  may  here  be  made  of 
imitations  of  genuine  coral  which,  from  the  most  delicate 
milk-white,  or  only  slightly  rose-tinged,  kinds  up  to  the 
deep  cinnabar-red  varieties,  can  be  produced  of  such  beauty 
as  to  be  distinguished  from  the  genuine  article  perhaps 
only  by  their  higher  lustre. 

Although  filled  celluloid  masses  colored  yellowish  in  a 
suitable  manner  closely  resemble  ivory  in  appearance,  they 
can  at  once  be  distinguished  from  ivory  by  the  absence  of 
the  peculiar  texture  characteristic  of  the  latter.  However, 


292  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

this  texture  is  also  successfully  imitated,  the  resemblance 
between  celluloid  imitations  and  genuine  ivory  becoming 
thereby  still  greater. 

For  this  purpose  plates  of  filled  celluloid  mass,  some  of 
them  pure  milk-white  and  others  of  a  color  inclined  to 
yellow,  are  used.  These  plates  are  alternately  laid  one 
upon  the  other,  hea.ted,  and  then  rolled.  By  the  pressure  of 
the  rolls  the  separate  plates  are  welded  together,  and  by 
being  stretched  under  the  rolls,  of  course,  become  con- 
stantly thinner,  so  that  the  layers  of  a  darker  and  lighter 
color  are  only  visible  upon  the  cross-section  in  the  form  of 
fine  lines  running  into  each  other.  If  a  plate  thus  rolled, 
previous  to  being  made  into  a  cane  head,  button,  etc.,  is 
bent  to  and  fro,  the  fine  lines  are  also  bent,  and  such  an 
article  has  to  be  very  closely  examined  in  order  to  find  out 
that  it  is  only  an  excellent  imitation  of,  instead  of  genuine, 
ivory. 

Tortoise  shell  can  be  so  closely  imitated  with  celluloid 
that  it  can  only  with  certainty  be  determined  by  a  chemi- 
cal examination,  whether  the  article  in  question  is  made  of 
genuine  tortoise  shell  or  is  an  imitation  of  it.  For  the  pur- 
pose of  imitating  tortoise  shell,  a  celluloid  plate  is  first  col- 
ored exactly  the  ground  color  of  genuine  tortoise  shell, 
solution  of  picric  acid  to  which  a  suitable  quantity  of  ani- 
line brown  has  been  added  being  used  for  the  purpose. 
The  peculiar  red-brown  markings  characteristic  of  tortoise 
shell  are  applied  by  means  of  a  paint-brush  with  aniline- 
brown  solution  to  which  a  small  quantity  of  fuchsin  has 
been  added.  Such  solutions  when  prepared  with  very 
strong  alcohol,  penetrate  deeply  into  the  celluloid  mass. 

The  celluloid  plates  used  for  imitations  of  tortoise  shell 
are  highly  polished  previous  to  being  colored  and  painted, 
this,  being  best  effected  by  pressing  them  against  a  rapidly 
revolving  cylinder  covered  with  a  soft  woolen  stuff.  Since 
the  painted  places  lose  somewhat  in  lustre,  the  plates  when 
finished  must  again  be  carefully  polished. 


CELLULOID.  293 

MOULDING    CELLULOID    ARTICLES. 

Pure  celluloid,  as  well  as  that  mixed  with  filling  sub- 
stances, can  in  a  simple  manner  be  brought  into  any  desired 
form,  it  becoming,  as  previously  mentioned,  so  plastic  at 
212°  F.,  as  to  equal,  in  this  respect  at  least,  warmed  wax. 

When  celluloid  is  to  be  converted  by  rolling  into  plates 
of  any  thickness,  the  simplest  plan  is  to  place  the  thicker 
plates  in  hot  water  until  sufficiently  softened,  and  then  roll 
them  out  as  thin  as  desired. 

In  case  celluloid  masses  of  greater  thickness  are  to  be 

FIG.  39. 


shaped  by  stamping  or  pressing,  it  is  advisable  to  use  a  spe- 
cial heating  apparatus  capable  of  holding  a  larger  quantity 
of  celluloid,  so  that  without  interruption  in  the  work,  heated 
pieces  may  be  constantly  taken  out,  and  replaced  by  pieces 
to  be  heated.  An  apparatus  very  suitable  for  this  purpose 
is  shown  in  Fig.  39.  A  is  a  cubical  box  of  stout  sheet-iron. 
It  is  surrounded  by  another  sheet-iron  box  B,  the  distance 
between  the  walls  of  the  two  boxes  being  2  to  2J  inches. 
The  outside  of  the  box  B,  with  the  exception  of  the  bottom, 
is  covered  with  thick  felt  and  the  latter  with  wood.  The 
outside  of  the  thick  wooden  door  of  the  box  A  is  also  cov- 
ered with  felt  and  wood.  From  the  top  of  the  box  B  as- 
cends a  pipe  R,  0.79  to  1.18  inch  in  diameter.  This  pipe 


294  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

terminates  in  a  spiral,  open  on  top,  in  a  cooling  vessel 
filled  with  cold  water.  The  space  between  the  boxes  A  and 
B  is  filled  with  water,  and  the  bottom  of  B  is  heated  by 
means  of  a  small  stove  upon  which  the  apparatus  stands, 
or,  if  the  latter  is  small,  by  a  gas  flame.  The  celluloid 
masses  are  placed  upon  zinc  plates  fixed  one  above  the 
other  in  the  box  A.  When  the  water  between  the  two 
boxes  has  been  brought  to  the  boiling  point,  the  temper- 
ature in  the  box  A  will  in  a  short  time  rise  to  212°  F.,  and 
the  celluloid  masses  will,  according  to  their  thickness,  be 
in  a  shorter  or  longer  time  heated  to  the  same  temper- 
ature. The  box  A  is  only  opened  for  taking  out  heated  cel- 
luloid, or  for  placing  pieces  to  be  heated  in  it. 

Since  the  water  by  boiling  evaporates,  it  would  be  nec- 
essary from  time  to  time  to  replenish  it.  This  is,  however, 
rendered  superfluous  by  the  cooling  arrangement,  by  means 
of  which  the  steam  rising  through  the  pipe  R  into  the  spiral 
portion  of  the  latter  in  the  cooling  vessel  is  condensed,  and 
the  hot  water  falls  back  into  the  space  between  the  two 
boxes.  When  work  for  the  day  is  finished  and  the  fire 
under  the  apparatus  extinguished,  the  water,  by  reason  of 
the  insulation  of  the  outer  box  by  felt  and  wood,  remains 
quite  hot  till  the  next  morning,  and  but  little  time  is  re- 
quired to  bring  it  to  the  boiling  point. 

Celluloid  tubes  are  made  as  follows :  A  plate  of  celluloid 
is  cut  rectangularly  in  such  a  way  that  it  accurately  fits 
around  a  cylinder  corresponding  to  the  inside  diameter  of 
the  tube  to  be  made.  The  cylinder  being  heated,  the 
softened  celluloid  plate  is  laid  around  it,  and  a  round  piece 
of  sheet  metal  is  pushed  over  the  plate  so  as  to  hold  it  in 
position  without  entirely  covering  it.  Fluid  celluloid  is 
applied  to  the  joint  of  the  plate,  and  the  whole  is  then  left 
untouched  till  the  celluloid  is  cold.  The  finished  tube  is 
then  drawn  from  the  cylinder. 

It  may  here  be  mentioned  that  for  the  purpose  of  joining 
two  pieces  of  celluloid,  it  has  been  recommended  to  soften 


CELLULOID.  295 

them  by  the  application  of  strong  alcohol,  and  then  press 
them  together.  Celluloid  solution  obtained  by  dissolving 
nitro-cellulose  and  camphor  in  ether  is,  however,  more 
suitable  for  the  purpose,  it  solidifying  in  a  very  short  time, 
and  the  two  pieces  are  then  joined  together  by  the  same 
mass  of  which  they  themselves  consist. 

If  celluloid  is  to  be  shaped  by  pressing,  it  is  advisable, 
especially  when  making  a  large  quantity  of  articles  of  the 
same  form,  to  put  the  lower  portion  of  the  mould  in  the 
press  in  such  a  way  that  it  can  constantly  be  kept,  by  means 
of  a  gas  flame,  at  a  temperature  which  need  not  be  above 
158°  F.  In  preparing  articles  from  heated  celluloid  in  a 
press  thus  arranged,  tearing  of  the  mass  on  the  edges  need 
not  be  feared,  and,  with  some  dexterity,  the  pressed  article 
can,  while  still  soft  and  without  losing  shape,  be  lifted 
from  the  mould,  the  latter  being  thus  left  available  for  the 
next  operation. 

Imitations  of  corals  may  be  made  in  various  ways,  accord- 
ing to  the  form  the  separate  pieces  are  to  have.  Corals  of 
cylindrical  shape  are  cut  with  a  circular  saw  from  sticks 
made  by  pressing.  Rounded-off  (barrel-shaped)  corals  are 
stamped  from  the  above-mentioned  cylindrical  sticks,  and 
pierced  in  the  lathe.  The  final  finish  is  given  to  the  corals 
by  brightening  them  by  means  of  rapidly  revolving  bobs 
covered  with  soft  cloth. 

The  use  of  celluloid  masses  for  the  manufacture  of  all 
kinds  of  combs  is  of  great  importance.  They  are  made  by 
first  rolling  a  celluloid  plate  in  such  a  way  that  one  of  its 
narrow  sides,  which  is  to  form  the  back  of  the  comb,  is 
thicker  than  the  other.  The  comb  is  then  stamped  from 
the  softened  plate.  The  teeth  are  cut  with  a  rapidly  re- 
volving circular  saw  kept  cool  by  water  dripping  upon  it, 
and  the  finished  comb  is  finally  polished. 

CLICHES    FROM    CELLULOID. 

A  very  important  application  of  celluloid  for  the  repro- 


296        CELLULOSE,  AND  CELLULOSE  PRODUCTS. 

duction  of  printed  matter  consists  in  its  use  for  cliches 
which,  independent  of  being  non-breakable,  are  very  dur- 
able so  that  thousands  of  impressions  may  be  made,  with- 
out their  sharpness  being  in  any  way  diminished.  The 
production  of  such  cliches,  either  from  a  form  of  type  or  a 
wood-cut,  is  a  very  simple  operation,  and  is  effected  as 
follows :  A  plaster  of  Paris  cast  is  first  made  of  the  form  or 
wood-cut,  the  best  quality  of  plaster  of  Paris  such  as  is  used 
for  art  castings  being  employed  for  the  purpose.  To  make 
the  cast  harder,  saturated  solution  of  alum  in  water  is  used, 
in  place  of  ordinary  water,  for  mixing  the  plaster  of  Paris. 
Such  cast  requires  a  longer  time  for  hardening  than  one 
prepared  in  the  usual  way,  but  it  possesses  much  greater 
hardness.  When  thoroughly  dry  the  cast  is  saturated  with 
solution  of  shellac  in  strong  alcohol ;  with  casts  from  wood- 
cuts this  saturation  is  effected  by  applying  the  shellac  solu- 
tion with  a  soft  brush. 

The  plaster  of  Paris  mould  is  then  placed  in  a  press  and 
covered  with  a  heated  celluloid  plate  of  suitable  thickness. 
The  press  is  then  slowly  and  very  uniformly  tightened  to 
give  the  softened  celluloid  time  to  penetrate  into  all  the  de- 
pressions of  the  mould.  The  press  is  finally  tightened,  and 
left  untouched  till  the  celluloid  is  cooled  to  the  ordinary 
temperature.  The  celluloid  plate  is  then  detached  from 
the  mould  by  carefully  knocking  the  latter  against  a  solid 
support,  and  the  mould,  which  is  not  in  the  least  damaged, 
may  be  used  for  making  another  cliche. 

When  a  celluloid  cliche  properly  made  is  examined  with 
a  magnifying  glass,  it  will  be  seen  that  the  smallest  details 
have  been  reproduced,  and  it  need  only  to  be  blocked  to  be 
ready  for  printing. 

Stamps,  the  text  of  which  is  composed  of  types  may  in  a 
similar  manner  be  made  from  celluloid,  such  stamps  hav- 
ing the  advantage  over  rubber  stamps  of  being  more  easjly 
made  and  being  more  durable. 


CELLULOID.  297 

COLLARS    AND    CUFFS    FROM    CELLULOID. 

Masses  of  celluloid  and  a  white  filling-substance  are  well 
adapted  for  the  manufacture  of  collars  and  cuffs  which,  as 
regards  appearance,  can  scarcely  be  distinguished  from 
such  articles  made  of  the  finest  quality  of  linen,  and  they 
have  the  advantage  of  greater  durability  and  being  more 
easily  cleansed,  though  the  latter  can  only  be  done  when 
properly  treated. 

The  white  masses  for  this  purpose  are  prepared  from 
celluloid  and  zinc-white,  or  magnesia,  or  chalk,  and  rolled 
out  to  plates.  Pieces  of  the  shape  of  the  collar  or  cuff  are 
then  stamped  from  these  plates. 

For  the  purpose  of  giving  these  pieces  the  appearance  of 
a  fine  quality  of  linen,  a  mould  is  made  as  follows :  A  col- 
lar of  fine  linen  is  used  as  a  model,  and  a  plaster  of  Paris < 
cast  made  of  it.  From  this  plaster  of  Paris  cast  hollow 
moulds  of  type  metai  are  made.  The  stamped  celluloid 
plates  being  heated  are  laid  in  the  moulds,  and  subjected  to 
pressure  by  means  of  a  press.  The  fine  threads  constituting 
the  tissue  of  the  collar  used  as  a  model  will  be  found  re- 
produced true  to  nature  upon  the  celluloid  so  that,  in 
appearance,  it  cannot  be  distinguished  from  the  linen  collar. 

Celluloid  collars  and  cuffs,  like  the  genuine  linen  articles, 
become  dirty  by  use,  and  it  is  claimed  they  can  be  cleansed, 
so  as  to  appear  like  new,  by  simply  brushing  them  with 
soap  and  water,  and  rinsing  in  water.  This,  however,  is 
not  in  accordance  with  the  facts,  it  being  impossible  in  this 
manner  to  remove  the  dirt,  and,  notwithstanding  a  vigorous 
use  of  the  brush,  the  article  does  not  become  perfectly  clean. 
The  reason  for  this  is  that  celluloid  mixed  with  a  large 
quantity  (up  to  50  per  cent.)  of  filling-substance  is  by  no 
means  an  impervious  material  like  pure  celluloid  ;  on  the 
contrary,  it  is  quite  a  porous  mass  in  which  the  particles  of 
dust  settle  so  firmly  that  they  cannot  be  removed  by  brush- 
ing with  soap  and  water.  The  impossibility  of  thoroughly 


298  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

cleaning  celluloid  cuffs  and  collars  may  probably  be  the 
reason  why  they  have  not  been  more  generally  introduced. 
For  the  production  of  celluloid  collars  and  cuffs  which 
can  actually  be  readily  cleansed,  it  would  seem  necessary  to 
provide  the  finished  article  with  an.  impervious  coating, 
pure  colorless  celluloid  being  used  for  this  purpose.  This 
coating  is  prepared  by  adding,  for  the  purpose  of  dilution, 
a  certain  quantity  of  absolute  alcohol  to  fluid  celluloid — 
i.  e.,  solution  of  nitro-cellulose  and  camphor  in  ether.  The 
finished  articles  are  for  one  moment  dipped  in  the  solution, 
whirled  around  to  remove  every  drop  of  solution,  and  hung 
up  free  in  the  air.  When  the  solvent  is  evaporated,  which 
will  be  the  case  in  a  very  short  time,  the  articles  will  look 
as  having  been  starched  with  gloss-starch,  their  beautiful 
appearance  being  due  to  the  thin  layer  of  colorless  celluloid 
with  which  they  have  been  provided.  Such,  so  to  say, 
lacquered  celluloid  collars  and  cuffs  may  be  cleansed  in  a 
very  simple  way  by  spreading  them  out  smoothly  and 
rubbing  with  a  sponge  dipped  in  lather,  drying,  and  vigor- 
ously rubbing  with  a  soft  cloth.  A  brush  should  not  be 
used,  as  by  rubbing  with  it  the  thin  layer  of  celluloid  would 
soon  lose  its  beautiful  gloss.  By  this  simple  treatment 
lacquered  collars  and  cuffs  can  be  actually  cleansed,  and 
besides  are  more  durable  than  linen  articles  which  after 
having  been  several  times  washed,  are  frequently  so  much 
the  worse  for  wear  as  to  be  useless. 

CELLULOID    FOR    DENTISTS'    USE. 

In  modern  times  celluloid  is  more  and  more  employed 
by  dentists,  it  having  gradually  supplanted  hard  rubber, 
which  was  formerly  in  general  use  for  the  manufacture  of 
sets  of  artificial  teeth. 

The  celluloid  to  be  used  for  this  purpose  must  be  of  ex- 
actly the  same  color  as  the  gums,  and  the  only  dye-stuff 
suitable  for  coloring  it  is  cinnabar,  on  account  of  its  indif- 
ference towards  the  action  of  the  saliva  and  food.  For  the 


CELLULOID.  299 

purpose  of  preparing  an  intimate  mixture  of  celluloid  and 
cinnabar,  the  latter  has  to  be  reduced  to  an  impalpable 
powder  by  levigation.  It  is  best  to  commence  the  operation 
by  covering  a  thin,  softened  plate  of  celluloid  with  cinnabar 
powder,  placing  another  also  very  thin  celluloid  plate  upon 
it,  and  joining  the  two  plates  by  rolling,  the  cinnabar  be- 
coming thereby  fixed.  The  plate  thus  obtained  is  folded 
together,  heated  and  again  rolled,  this  operation  being  re- 
peated till  the  celluloid  is  uniformly  colored  throughout. 
The  work  of  preparing  in  this  manner  a  uniform  mass 
being  quite  troublesome,  it  would  seem  advisable  to  prepare 
at  one  operation  a  larger  quantity  of  such  celluloid,  and 
make  it  finally  into  plates  of  the  thickness  suitable  for  the 
use  of  dentists. 

An  exact  impression  of  the  gums  and  jaw  as  required  for 
making  a  set  of  artificial  teeth  is  made,  as  is  well  known, 
with  plaster  of  Paris,  and  the  negative  thus  obtained  is 
made  use  of  for  preparing  the  plates.  In  making  these 
plates  from  rubber,  an  impression  in  soft  rubber  is  made 
from  the  plaster  of  Paris  negative,  and  heated  in  the  vulcan- 
izing apparatus  till  it  is  converted  into  hard  rubber.  In 
working  with  celluloid,  the  preparatory  operations  are  the 
same  as  with  rubber.  The  celluloid  which  is  to  be  used  for 
the  plates  is  heated  till  it  is  very  plastic,  and  then  firmly 
pressed  upon  the  plaster  of  Paris  cast,  remaining  thus  under 
pressure  till  the  whole  is  cooled  down  to  the  ordinary  tem- 
perature. 

The  temperature  to  which  the  celluloid,  to  be  used  for 
plates,  has  to  be  heated,  is  given  by  dentists  as  282°  F. 
However,  this  is  probably  too  high,  celluloid  at  this  degree 
of  heat  approaching  the  point  at  which  it  is  decomposed.  In 
our  opinion,  a  temperature  of  266°  to  275°  F.  is  amply  suf- 
ficient to  make  the  celluloid  so  plastic  as  not  to  require  even 
especially  high  pressure  to  force  it  into  the  finest  depres- 
sions of  the  mould.  Care  must,  however,  be  taken  to  heat 
the  celluloid  throughout  to  the  above-mentioned  degree 
before  pressing  is  commenced. 


300  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

OBJECTS  OF  ART  FROM  CELLULOID. 

By  reason  of  its  great  plasticity,  when  heated,  celluloid 
may  to  advantage  be  used  for  the  manufacture  of  all  kinds 
of  inlaid  work,  and  with  it  as  a  basis-material,  beautiful 
mosaics  can  be  produced,  as  well  as  fancy  articles  inlaid 
with  metal,  the  latter  being  generally  made  of  celluloid 
masses  representing  an  imitation  of  ivory  or  tortoise  shell. 

The  metals  used  for  these  incrustations  are  gold  and  silver 
for  valuable  articles,  and  bronze,  copper,  and  aluminium 
for  cheaper  goods.  The  metals  are  used  in  the  form  of  very 
thin  sheets,  from  which  are  cut  by  means  of  suitable  dies, 
stars,  bands,  leaves,  ornaments,  monograms,  etc. 

These  small  particles  of  metal  are  attached  to  the  cellu- 
loid by  moistening  them  with  strong  alcohol,  or  still  better 
with  fluid  celluloid,  and  placing  them  in  their  proper  posi- 
tions for  the  execution  of  a  fixed  design. 

When  the  entire  design  has  thus  been  produced,  the 
celluloid  plate  is  placed  upon  a  firm,  level  support,  for  in- 
stance a  piece  of  thick  zinc-sheet,  and  uniformly  heated  to- 
gether with  the  latter  to  257°  F.  The  plate  together  with 
the  support  is  then  drawn  through  rolls,  a  very  slight  pres- 
sure being  first  given  for  the  purpose  of  pressing  the  parti- 
cles of  metal  into  the  soft  celluloid  mass.  In  passing  the 
plate  for  the  second  time  through  the  rolls  a  somewhat 
greater  pressure  is  given,  and  the  latter  is  finally  increased 
to  such  an  extent  that  on  touching  the  plate  with  the 
fingers  no  elevation  is  noticed,  this  being  proof  of  all  the 
metallic  particles  having  been  sunk  into  the  plate.  The 
latter,  when  cold,  is  lightly  ground  and  then  highly 
polished.  When  such  encrusted  plates  have  to  be  bent,  as 
is  necessary,  for  instance,  in  the  manufacture  of  cigar  cases 
or  pocket  books,  a  metallic  negative  form  has  to  be  used. 
The  celluloid  plate  is  laid  upon  this  form  and  sufficiently 
heated  to  allow  of  it  being  readily  bent  over  it. 


CELLULOID.  301 

CELLULOID  MOSAICS. 

An  entirely  original  application  of  celluloid  masses  is 
their  use  for  the  production  of  mosaics  equal  in  appearance 
to  those  of  polished  stones  (pietra  dura  mosaics)  chiefly  made 
in  Florence. 

Celluloid,  as  previously  mentioned,  may  be  colored  any 
shade,  and  by  filling  it  with  colored  powders,  masses  of  any 
desired  color  may  be  produced.  By  coloring  celluloid,  for 
instance,  blue  with  ultra-marine  and  pressing  small  laminae 
of  mica  into  the  colored  mass,  a  body  is  obtained  which 
bears  a  close  resemblance  to  the  valuable  mineral  known  as 
lapis  lazuli.  By  partly  coloring  white  celluloid,  imitations 
very  true  to  nature  of  variegated  marble  may  be  obtained, 
etc. 

Celluloid  plates  thus  colored  may  be  used  for  the  execu- 
tion of  works  of  art  closely  resembling  genuine  Florentine 
mosaics,  but,  of  course,  costing  much  less  to  produce.  Such 
mosaics  are  produced  by  cutting  out  by  means  of  dies  from 
the  basis-plate  of  celluloid  the  portions  which  are  to  be  filled 
in  by  differently-colored  masses.  With  the  same  dies  por- 
tions are  then  cut  from  colored  celluloid  plates,  these  por- 
tions, of  course,  fitting  exactly  into  the  empty  spaces  of  the 
basis-plate.  To  prevent  the  celluloid  plates  from  cracking 
while  punching  out  the  pieces,  they  are,  previous  to  the 
operation,  heated  to  between  122°  and  140°  F. 

In  executing  the  design  a  painted  picture  is  followed,  the 
celluloid  pieces  which  have  been  cut  from  colored  plates 
being  placed  in  the  proper  empty  spaces  of  the  basis-plate, 
the  latter  resting  upon  a  level  zinc-plate.  When  the  design 
has  been  executed,  it  is  heated  together  with  the  support, 
till  the  celluloid  becomes  soft,  and  is  then  passed  through 
rolls,  by  the  pressure  of  which  the  firm  union  of  all  the 
celluloid  pieces  to  a  whole  is  effected.  The  final  finish  is 
given  to  the  plate  by  grinding  and  polishing.  Before  pol- 
ishing, the  color  effects  of  certain  parts,  where  it  appears 


302  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

necessary,  may  be  heightened  by  carefully  painting  them 
with  tar  colors  dissolved  in  alcohol. 

As  previously  mentioned,  such  mosaic  designs  closely  re- 
semble in  appearance  those  made  of  differently-colored 
stones,  but  of  course  are  much  cheaper. 

CELLULOID    LACQUER. 

A  solution  of  nitro-cellulose  and  camphor  in  ether  forms 
the  substance  which  has  in  this  work  been  repeatedly  de- 
signated as  celluloid  solution,  and  to  convert  it  into  solid 
celluloid  nothing  has  to  be  done  but  to  allow  the  solvent  to 
evaporate.  If  a  solution  of  celluloid  be  poured  upon  a  level 
glass  plate  in  such  a  way  that  the  thick  fluid  spreads  in  a 
thin  layer  over  the  glass  plate,  a  thin  plate  of  celluloid  is 
obtained  after  the  evaporation  of  the  solvent,  which  may 
be  used  as  so-called  films  for  photographic  purposes. 

By  mixing  celluloid  solution  with  a  suitable  quantity  of 
strong  alcohol,  a  fluid  is  obtained  which  dries  more  slowly 
upon  the  glass  plate  than  the  solution  containing  only 
ether,  but  leaves  behind  an  exceedingly  thin,  though  per- 
fectly homogeneous,  film  of  celluloid.  By  dipping  an 
article  in  this  solution,  or  applying  it  with  a  brush,  and 
allowing  it  to  dry,  an  exceedingly  thin  coating  of  celluloid 
is  formed,  covering  the  entire  surface  of  the  article  and  pro- 
tecting it  from  the  effects  of  dust  and  moisture,  thus  pos- 
sessing all  the  properties  which  may  be  demanded  from  an 
excellent  quality  of  lacquer. 

No  matter  how  thin  such  coatings  of  celluloid  may  be, 
they  are  perfectly  water-proof,  and  even  the  most  delicate 
articles  may  be  cleansed  with  a  sponge  and  soap.  The 
coating  may  be  so  thin  as  not  to  be  noticeable,  and  if  some- 
what thicker,  imparts  to  the  articles  the  beautiful  lustre 
characteristic  of  celluloid.  Thin  coatings  are  especially  of 
value  for  the  protection  of  maps,  copper  and  steel  engrav- 
ings, as  well  as  drawings  in  general.  By  coating  both  the 
face  and  back,  of  a  map,  water-color  painting,  or  printed 


CELLULOID.  303 

sheet,  with  dilute  celluloid  solution  and  allowing  the  coat  to 
dry,  the  paper  is  rendered  almost  indifferent  to  moisture. 
In  case  it  has  become  dirty  by  frequent  handling,  it  can 
without  fear  be  cleansed  by  spreading  it  out  upon  a  support 
and  washing  with  a  sponge  and  soap  water,  all  the  dirt 
adhering  to  the  celluloid  being  thus  removed  without  the 
underlying  paper  becoming  even  moist. 

A  very  thin  layer  of  celluloid  affords  an  excellent  pro- 
tection for  metals  against  rust,  turning  black  and,  in  fact, 
against  all  external  influences.  Collections  of  armor, 
weapons,  etc.,  have  to  be  constantly  watched  to  prevent 
rusting.  However,  when  once  made  bright  and  then  pro- 
vided with  a  scarcely  perceptible  layer  of  celluloid,  they 
retain  their  polish  and  need  only  from  time  to  time  be  freed 
from  dust  by  wiping  with  a  woolen  cloth,  to  be  kept  in 
perfect  condition.  Even  if  such  articles  are  kept  in  a  damp 
room,  they  show  no  trace  of  rust,  the  iron  under  the  air- 
tight coating  of  celluloid  being  excluded  from  the  action  of 
moist  air. 

The  above-mentioned  excellent  properties  of  thin  coat- 
ings of  celluloid  have  led  to  the  extensive  use  of  celluloid 
solutions  as  lacquers.  Numerous  receipts  for  the  prepara- 
tion of  such  lacquers  have  been  published,  some  of  them 
containing  ingredients,  the  effect  of  which  in  the  composi- 
tion is  beyond  comprehension.  A  detailed  enumeration  of 
such  receipts  is  here  out  of  the  question,  and  only  the  prin- 
ciples will  be  given  according  to  which  celluloid  lacquers 
for  various  purposes  have  to  be  prepared,  the  main  point 
being  whether  a  lacquer  yielding  a  strong,  tenacious  coat- 
ing is  to  be  made,  or  one  possessing  a  certain  degree  of 
flexibility  and  elasticity. 

The  basis-material  of  all  celluloid  lacquers  brought  into 
commerce  under  various  names,  such  as  kristaline,  zapon, 
victoria  lacquer,  etc.,  is  nitro-cellulose  of  a  composition  re- 
presenting the  soluble  form.  For  the  preparation  of  the 
various  kinds  of  nitro-cellulose,  the  reader  is  referred  to  the 
detailed  description  given  in  a  previous  chapter. 


304  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

An  excellent  celluloid  lacquer  may  be  prepared  by 
simply  dissolving  nitro-cellulose  and  camphor  in  ether. 
However,  by  reason  of  the  rapid  evaporation  of  the  ether, 
such  a  solution,  when  applied  in  thin  layers,  dries  almost 
instantly,  especially  on  a  warm  day,  which  is  frequently 
inconvenient.  It  is,  however,  quite  suitable  for  lacquering 
smaller  articles  by  dipping,  whirling  off  the  excess  of  fluid, 
and  swinging  the  articles  for  a  few  seconds  to  and  fro, 
whereby  they  become  perfectly  dry,  but  it  is  not  adapted 
for  larger  articles,  as  it  dries  almost  under  the  brush. 

Celluloid  lacquers  are,  therefore,  best  prepared  with  the 
use  of  a  less  volatile  fluid,  and,  besides  ether,  quite  a  num- 
ber of  solvents  for  nitro-cellulose,  such  as  alcohol,  acetone, 
potato  fusel  oil  (amyl  alcohol),  benzine,  etc.,  may  be  used 
for  the  purpose. 

The  best  results,  as  has  been  found,  are  obtained  by 
using  for  the  preparation  of  the  solution  a  mixture  of  equal 
parts  of  pure  ether  and  strong  rectified  alcohol,  and  by  the 
process  given  below  a  lacquer  is  obtained  which,  as  com- 
pared with  other  similar  products,  excels  in  clearness  and 
lustre. 

The  perfectly  dry  nitro-cellulose  is  weighed  and  brought 
together  with  the  corresponding  quantity  of  camphor — 2 
parts  by  weight  of  nitro-cellulose  to  1  part  by  weight  of 
camphor — into  a  wide-necked  bottle,  which  can  be  closed 
air-tight  with  a  well-fitting  cork  coated  with  paraffine. 
The  lower  end  of  the  cork  is  furnished  with  a  small  hook 
for  the  suspension  of  a  small  bag  of  very  close  fine  linen 
and  made  in  the  form  of  a  sausage,  which  is  filled  with  the 
nitro-cellulose. 

The  camphor  having  been  brought  into  the  bottle,  the 
mixture  of  equal  parts  of  ether  and  alcohol  is  poured  over 
it,  and  the  bottle  is  frequently  shaken  till  all  the  camphor 
is  dissolved.  The  bag  containing  the  nitro-cellulose  is  then 
suspended  to  the  hook,  the  bottle  closed  air-tight  with  the 
cork,  and  placed  where  it  is  protected  from  shocks.  The 


CELLULOID.  305 

nitro-cellulose  at  first  swells  up  very  much,  and  then  grad- 
ually dissolves  in  the  fluid,  the  linen  bag  acting  as  a  filter, 
and  retaining  the  portion  of  the  nitro-cellulose  which  only 
swells  up  without  dissolving.  A  perfectly  clear  solution  is 
thus  after  some  time  obtained. 

The  solution  thus  prepared  is,  as  a  rule,  too  thickly-fluid 
for  direct  use  as  a  lacquer,  but  being  miscible  in  every  pro- 
portion with  alcohol,  a  lacquer  of  any  desired  consistency 
can  be  readily  obtained. 

When  applied  to  an  article,  celluloid  lacquer  prepared 
according  to  the  above-described  process,  yields  a  perfectly 
colorless  coating.  It  may,  however,  be  given  any  desired 
color  by  mixing  the  clear  solution  with  a  tar-color  soluble 
in  alcohol.  A  saturated  solution  of  the  coloring  matter  in 
alcohol  is  first  prepared  and  filtered,  and  a  sufficient  quan- 
tity of  it  is  added  to  the  colorless  lacquer  to  give  it  the 
desired  shade  of  color. 

Very  beautiful  effects  may  be  produced  with  colored 
celluloid  lacquers  especially  upon  paper  and  bright  metals, 
and  they  can  to  advantage  be  used  for  lacquering  fancy 
paper  and  small  metal  articles.  Artificial  flowers  of  paper 
when  dipped  in  colored  celluloid  lacquer  exhibit,  after  dry- 
ing, a  very  beautiful  lustre  and  do  not  become  unsightly 
by  dust,  the  latter  adhering  only  loosely  to  the  smooth 
coating  and  may  be  readily  blown  off.  Such  flowers  may 
even  be  cleansed  by  sprinkling  them  by  means  of  an  atom- 
izer with  water  until  the  pure  color  reappears. 

An  important  application  of  celluloid  lacquers  is  for  the 
conservation  of  metals.  As  previously  mentioned,  collec- 
tions of  armor  and  weapons  can  in  the  simplest  manner  be 
protected  from  rust  by  a  coating  of  celluloid,  and  metallic 
articles  of  every  description  may  in  the  same  manner  be 
preserved,  so  that  rusting  becomes  impossible,  and  for  the 
purpose  of  cleansing  they  need  only  be  wiped  with  a  soft 
cloth. 

A  coating  of  celluloid  is  said  to  be  of  special  importance 
20 


306  CELLULOSE,  AND    CELLULOSE    PKODUCTS. 

for  metallic  articles  which  come  in  contact  with  sea  water. 
By  reason  of  its  content  of  salt,  sea  water  acts  very  energet- 
ically upon  metals,  and  constant  cleaning  and  oiling  are 
required  to  protect  them  from  becoming  rusty,  but  metal 
articles  coated  with  celluloid  lacquer  remained  bright  when 
brought  repeatedly  in  contact  with  sea  water.  The  por- 
tions of  iron  vessels  exposed  to  the  action  of  sea  water  are, 
as  is  well  known,  strongly  attacked,  and  it  has  been  pro- 
posed to  protect  them  by  a  coat  of  celluloid.  While  such  a 
coat  would,  without  doubt  produce  a  favorable  effect,  a 
single  application  of  thin  celluloid  lacquer  would  scarcely 
suffice.  The  use  of  a  thickly-fluid  lacquer  would  be  re- 
quired, and  several  coats  of  it  would  have  to  be  applied  in 
order  to  fix  upon  the  iron  a  layer  of  celluloid  about  0.039 
inch  thick,  such  a  layer  being  of  sufficient  thickness  not  to 
be  worn  off,  even  after  a  long  time,  by  the  friction  of  the 
water.  Special  experiments  in  this  direction  are  said  to 
have  been  attended  by  excellent  results,  and  it  is  claimed 
that  no  barnacles  adhere  to  the  smooth  surface  of  the  cellu- 
loid, as  is  otherwise  the  case. 

CELLULOID-LIKE  MASSES  WITHOUT  AN  ADDITION  OF  CAMPHOR. 

The  pronounced  odor  of  camphor  of  many  articles  pre- 
pared from  celluloid  is  in  many  cases  objectionable,  and 
efforts  have  been  made  to  substitute  for  the  camphor  other 
substances  which,  together  with  nitro-cellulose,  would  yield 
a  product  equal  in  physical  properties  to  celluloid. 

To  judge  from  the  large  number  of  substances  proposed 
for  this  purpose,  it  may  be  supposed  that  either  all  of  them 
yield  with  nitro-cellulose  substances  whose  properties  corre- 
spond with  those  of  celluloid,  or,  what  is  more  probable, 
that  more  favorable  results  are  obtained  with  some  of  them 
than  with  others. 

According  to  a  statement  of  the  Societe  generate  pour  la 
Fabrication  des  mailer es  plastiques,  the  camphor  in  the  man- 
ufacture of  celluloid  may  be  entirely  replaced  by  naphtha- 


CELLULOID.  307 

/ 

line.  However,  the  odor  of  naphthaline  being  still  more 
intense  and  offensive  to  most  people  than  camphor,  the 
product  obtained  presents  no  other  advantage  over  celluloid 
than  that  of  being  cheaper. 

Zuhl  and  Eisemann  replace  the  camphor  partly  or  en- 
tirely by  a  series  of  various  bodies.  They  enumerate  in 
their  patent  as  suitable  for  this  purpose :  a  and  /3  naphthyl 
acetate,  phenoxyl  or  naphthoxyl  acetic  acids,  their  anhy- 
drides or  esters,  methylnaphthylketone,  dinaphthylketone, 
methyloxynaphthylketone  or  dioxydinaphthylketone,  and 
the  esters  of  the  oxanyl  acids.  By  working  up  25  kilo- 
grammes (55  Ibs.)  of  oxanyl  acid  methyl  ester  either  by 
itself,  or  together  with  a  solvent,  and  75  kilogrammes  (165 
Ibs.)  of  nitro-cellulose,  a  suitable  product  is  obtained,  as 
well  as  with  the  use  of  30  kilogrammes  (66  Ibs.)  of  oxanyl 
acid,  benzyl  ester  and  100  kilogrammes  (220  Ibs.)  of  nitro- 
cellulose. In  place  of  camphor,  according  to  the  above 
mentioned  authors,  may  also  be  used  :  triphenyl  phosphate, 
tricresyl  phosphate  or  trinaphthyl  phosphate,  or  finally  the 
monohalogen  products  of  substitution  of  the  aromatic 
hydrocarbons,  so  that  camphor  may  be  entirely  banished 
from  the  manufacture  of  celluloid. 

J.  R.  Goldsmith  uses  in  place  of  camphor,  or  as  a  partial 
substitute  for  it,  acetodichlorhydrin,  diacetochlorhydrin  and 
monoacetomonochlorhydrin. 

According  to  a  communication  of  the  Farbwerke,  formerly 
Meister,  Lucius  and  Briinig,  the  camphor  in  the  manufac- 
ture of  celluloid  may  be,  either  entirely  or  partly,  replaced 
by  aromatic  sulpho-acids  derivatives,  derived  from  chlorides, 
esters  and  amides.  Celluloid-like  masses  without  camphor 
may  be  prepared  with  the  use  of  neutral  phtalic  acid  alkyl 
ester  and  phtalic  acid  alphyl  ester.  The  following  example 
may  here  be  given  :  Dissolve  1000  parts  of  phtalic  acid 
diphenyl  ester  in  alcohol  and  add  to  the  solution  2000  parts 
of  nitro-cellulose.  When  the  nitro-cellulose  is  completely 
swelled  up,  the  mass  is  further  worked  in  the  usual  way. 


308  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

The  corresponding  cresyl  ester  of  the  above-mentioned 
bodies  may  in  the  same  manner  be  used. 

The  Deutsche  Celluloid  Fabrik  at  Leipzig-Plagwitz  re- 
places camphor  in  the  manufacture  of  celluloid  by  acetyl 
derivatives  of  secondary  aromatic  amines. 

No  matter  what  substitute  may  be  used  for  camphor  in 
the  manufacture  of  celluloid,  practical  success  can  be 
achieved  only  with  a  substance  which  yields  a  product, 
that,  as  regards  transparency,  elasticity  and  plasticity  when 
heated,  as  well  as  capacity  of  being  colored,  corresponds 
with  camphor-celluloid,  and  is  entirely  or  nearly  colorless, 
and  can  be  produced  at  the  same  cost.  :  •  r 


XIII. 

RUBBER  COMPOUNDS. 

BY  rubber  compounds  are  understood  masses  consisting 
partly  of  rubber  with  the  addition  of  other  substances,  these 
additions  being  generally  made  for  the  purpose  of  produc- 
ing a  cheaper  article,  though  in  some  cases  also  to  impart 
to  the  rubber  properties  otherwise  not  possessed  by  it. 
From  rubber  alone,  for  instance,  masses  with  properties 
like  those  of  whalebone,  especially  as  regards  tenacity  and 
elasticity,  could  not  be  produced,  but  it  can  be  done  with 
the  use  of  suitable  additions. 

The  principal  substances  used  as  additions  to  rubber  are 
resins — especially  shellac — antimony  pentasulphide  or  gold 
sulphur,  and  coal  tar  pitch.  As  indifferent  filling  sub- 
stances, any  powdered  materials  insoluble  in  water  may  be 
used,  for  instance,  chalc,  ferric  oxide  (colcothar  or  rouge) 
or  calcined  magnesia.  The  use  of  the  latter  may  be  espe- 
cially recommended,  because  with  great  bulk,  it  has  a  com- 
paratively slight  specific  gravity,  and  articles  filled  with  it 
are  not  conspicuous  by  great  weight. 

Of  the  resins,  shellac  is  most  frequently  used,  it  being 
harder  and  less  brittle  than  other  varieties,  and  for  our  pur- 
poses the  dark-red  article  known  in  commerce  as  ruby  shel- 
lac is  most  suitable. 

Of  the  pitch-like  substances,  large  quantities  of  the  best 
grades  of  asphalt,  as  well  as  coal-tar  pitch,  are  used  as  ad- 
ditions to  rubber  compounds.  Asphalt  combines  readily 
with  rubber,  but  has  the  disadvantage  of  a  quite  low  melt- 
ing point,  so  that  compounds  containing  a  certain  quantity 

(309) 


310  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

of  it,  become  soft  at  a  comparatively  low  temperature  and 
generally  lose  the  greater  portion  of  their  elasticity. 

Coal-tar  pitch,  large  quantities  of  which  are  at  present 
produced,  is  distinguished  by  having  a  much  higher  melt- 
ing point  than  asphalt,  and  besides  yields  compounds  of 
considerably  greater  hardness,  so  that  for  this  reason  alone 
it  is  to  be  preferred.  Coal-tar  pitch  is  prepared  by  heating 
coal  tar  in  a  still  until  the  greater  portion  of  the  volatile 
bodies  is  distilled  over,  and  in  the  still  remains  a  residue 
which,  on  cooling,  congeals  to  a  solid  mass  of  a  deep-black 
color.  The  last  products  of  distillation  escaping  from  the 
coal-tar  pitch  only  at  a  temperature  of  more  than  612°  F., 
softening  of  the  compound  containing  this  pitch  need  not 
be  feared. 

Manufacturers  engaged  in  the  preparation  of  rubber 
masses  apply  to  their  products  various  names,  which  gener- 
ally refer  to  some  special  property.  Thus,  masses  possess- 
ing not  much  elasticity  but  a  high  degree  of  plasticity,  are 
designated  as  plastite,  while  others  distinguished  by  great 
tenacity  and  flexibility  are  known  as  artificial  whalebone  or 
balenite.  Masses  resembling  in  their  properties  and  appear- 
ance ivory,  are  called  ebonite,  etc. 

PLASTITE    MASSES. 

The  compounds  to  which  this  term  has  been  applied  are 
frequently  brought  into  commerce  under  the  name  of  hard 
rubber.  This  designation  is,  however,  misleading,  genuine 
hard  rubber  consisting  only  of  a  mixture  of  rubber  and  sul- 
phur, which  has  been  exposed  to  a  suitably  high  tempera- 
ture. It  is  of  a  deep  black  color,  quite  hard,  and  neverthe- 
less possesses  a  considerable  degree  of  elasticity.  Plastite 
masses  are  also  of  a  deep  black  color  and  are  distinguished 
by  considerable  hardness,  but  instead  of  being  elastic,  are 
quite  brittle.) 

There  are  quite  a  number  of  receipts  for  the  preparation 
of  plastite  masses.  In  some  of  them  ingredients  are  given, 


RUBBER    COMPOUNDS.  311 

the  effect  of  which  cannot  in  any  manner  be  explained, 
and  it  may  be  supposed  they  have  been  introduced  simply 
for  the  purpose  of  making  the  receipt  appear  as  something 
new. 

A  plastite  mass  possessing  excellent  properties  has,  accord- 
ing to  Raimund  Hoffer,  the  following  composition  : 

Kubber 100  parts  by  weight. 

Sulphur 20  to  25  parts  by  weight. 

Magnesia 40  to  50  parts  by  weight. 

Pentasulphide  of  antimony 40  to  50  parts  by  weight. 

Coal-tar  pitch 50  to  60  parts  by  weight. 

The  masses  are  prepared  as  follows :  The  rubber  is 
worked  by  itself  in  the  kneading  machine  till  sufficiently 
soft,  when  the  finely  pulverized  ingredients  are  added,  and 
the  whole  is  worked  by  mechanical  means  till  a  uniform 
mass  results.  The  latter  is  then  pressed  under  high  pres- 
sure in  iron  moulds,  and  vulcanized  in  the  same  manner  as 
hard  rubber.  The  plastite  thus  obtained  is  of  a  deep  black 
color,  possesses  considerable  hardness,  aud  takes  a  high 
polish.  It  is  at  present  quite  extensively  used  in  the  in- 
dustries, since  a  large  number  of  articles  which  were  form- 
erly made  by  hand  from  wood,  metal,  horn,  etc.,  can  be 
manufactured  from  it  in  a  more  simple,  and  therefore 
cheaper,  way. 

ELASTIC    RUBBER    MASSES. 

With  reference  to  their  properties,  elastic  rubber  masses 
are  a  medium  between  rubber  vulcanized  in  the  ordinary 
way  and  hard  rubber,  and  by  a  suitable  change  in  their 
quantitative  compositions,  they  may  be  made  either  harder 
or  more  elastic. 

The  chief  requisites  of  masses  of  this  kind  are  elasticity 
and  tenacity  equal  to  whalebone,  and  products  are  now 
prepared  which,  as  regards  these  properties,  answer  all 
demands,  and  for  many  purposes  have  supplanted  the  gen- 
uine article. 


312  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

A  mass  serving  for  the  manufacture  of  balenite  is  com- 
posed of  the  following  ingredients  : 

Rubber 100  parts  by  weight. 

Kuby  shellac 20  parts  by  weight. 

Calcined  magnesia 20  parts  by  weight. 

Sulphur      25  parts  by  weight. 

Pentasulphide  of  antimony 20  parts  by  weight. 

The  ingredients  are  mixed  in  the  same  manner  as  given 
for  plastite.  However,  the  degree  of  elasticity  and  tenacity 
depends  to  a  great  extent  on  the  temperature  at  which  vul- 
canizing is  effected  ;  the  lower  the  temperature  the  more 
elastic  the  finished  mass  will  be,  and  the  higher  the  tem- 
perature the  more  closely  the  product,  as  regards  its  proper- 
ties, will  approach  hard  rubber. 

Balenite  finds  extensive  application  in  the  industries.  It 
is,  for  instance,  much  used  as  a  substitute  for  whalebone  in 
the  manufacture  of  corsets,  it  being  even  superior  to  the 
latter  as  regards  flexibility.  Suitably-shaped  plates  of  it 
are  used  for  arm  and  leg  splints  in  surgery,  and  the  bob- 
bins for  cotton  spinning  are  now  largely  made  of  it.  On 
account  of  its  light  weight  and  indestructibility,  it  may  be 
highly  recommended  for  the  manufacture  of  gunstocks. 

RUBBER-LEATHER. 

A  product  brought  into  commerce  under  this  name, 
though  possessing  excellent  qualities,  has  found  but  little 
application  in  the  industries.  As  indicated  by  its  name,  it 
is  claimed  to  have  the  properties  of  leather.  However,  as 
regards  tenacity  and  durability,  rubber-leather,  like  all  such 
artificial  products,  cannot  bear  comparison  with  actual 
leather,  though  in  quality  it  surpasses  perhaps  all  prepara- 
tions of  a  similar  character.  As  compared  with  actual 
leather  it  is  distinguished  by  great  flexibility  and  imperme- 
ability to  moisture. 

Rubber-leather  is  prepared  as  follows :  A  rubber  solution 
is  first  prepared,  or  a  thick,  mucilaginous  and  much-swollen 


RUBBER    COMPOUNDS.  313 

mass  by  working  rubber  together  with  a  solvent  such  as  oil 
of  turpentine  or  benzine.  Waste  fibres  of  all  kind,  such  as 
flax,  jute,  hemp,  etc.,  are  then  incorporated  with  the  mass, 
it  being  sought  to  bring  ,into  it  as  many  fibrous  substances 
as  possible.  When  the  mass  has  finally  acquired  such  con- 
sistency that  it  cannot  be  further  worked  between  the  rolls, 
it  is  stretched  out  into  a  long,  thin  band.  This  band  is  sev- 
eral times  made  into  a  lump  which  is  again  stretched  out 
by  rolling.  By  this  repeated  rolling,  the  fibres  are  piled  in 
different  directions,  forming,  so  to  say,  a  kind  of  felt.  The 
mass  is  finally  rolled  into  thin  plates  and  allowed  to  lie  in 
the  air  till  the  solvent  has  evaporated. 

In  the  rubber-leather  thus  obtained,  the  separate  fibres 
are  intimately  cemented  together  by  the  rubber,  and  the 
material  is  distinguished  by  great  tenacity.  As  shown  by 
special  experiments,  a  product  of  still  greater  tenacity  is 
obtained  by  impregnating  closely  woven  tissues  of  not  too 
fine  a  quality  with  rubber  emulsion,  and  uniting  two  or 
more  such  tissues  by  vigorous  pressure.  The  product  ob- 
tained in  this  manner,  even  if  quite  thin,  possesses  such 
tenacity  as  to  be  actually  suitable  for  shoe  uppers,  carriage 
covers,  etc.  However,  the  cost  of  producing  such  materials 
is  so  high  that  they  are  more  expensive  than  genuine 
leather,  and  this  is  very  likely  the  chief  reason  why  they 
have  not  been  more  generally  introduced  in  practice.  As 
mentioned  in  speaking  of  the  various  uses  of  viscose,  tissues 
may  now  be  made  very  tenacious  and  resisting  by  suitable 
treatment  with  thick  viscose  solutions,  they  being  in  every 
respect  equal  to  tissues  impregnated  with  rubber,  but  much 
cheaper. 

MARINE    GLUE. 

This  term  is  applied  to  a  valuable  rubber  compound, 
which  is  of  special  importance  when  metallic  articles  com- 
ing alternately  in  contact  with  water  and  air  are  to  be  pro- 
tected from  rust. 


314  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

Marine  glue  is  best  prepared  as  follows :  Small  pieces  of 
rubber  are,  by  the  application  of  heat,  allowed  to  swell  up 
in  a  quantity  of  anhydrous  petroleum  amounting  to  twelve 
times  their  weight.  The  mixture  having  been  made  uni- 
form by  continued  stirring  and  gentle  heating,  six  times 
the  quantity  of  ruby  shellac  or  asphalt — or  in  place  of  the 
latter  coal-tar  pitch — is  introduced.  The  mass  is  then 
made  more  thinly-fluid  by  stronger  heating,  and  stirred  till 
uniform  throughout. 

For  use,  the  marine  glue  is  carefully  melted  and  heated 
till  thinly-fluid.  The  temperature  required  for  this  pur- 
pose being  such  as  to  exclude  its  application  by  means  of 
bristle  brushes,  brushes  of  thin  elastic  wire  are  employed. 

By  adding  to  the  marine  glue,  while  it  is  being  prepared, 
a  few  per  cent,  of  sulphur,  and  heating  the  articles  coated 
with  it  to  above  392°  F.,  the  mass  is  changed  as  is  the  case 
with  all  rubber  compounds  when  heated  to  high  tempera- 
tures ;  the  rubber  is  converted  into  hard  rubber.  Articles 
thus  treated  are  actually  coated  with  a  thin,  but  firmly  ad- 
hering, layer  of  hard  rubber,  forming  one  of  the  most  dur- 
able and  resisting  coats  of  lacquer  known. 


XIV. 

RUBBER  SUBSTITUTES. 

IT  is  a  well-known  fact  that  the  production  of  rubber  does 
not  keep  up  with  its  consumption.  The  constantly  increas- 
ing demand  for  it  cannot  be  met,  and  the  price  of  it  goes 
steadily  up,  though  larger  quantities  than  ever  before  are 
now  brought  into  commerce  from  the  Congo  districts. 

This  steadily  increasing  demand  for  rubber  has  also  in- 
duced the  chemist  to  seek  for  substances  possessing  proper- 
ties resembling  those  of  rubber,  but  up  to  the  present  time 
none  has  been  found,  which  equals  it  as  regards  elasticity, 
tenacity,  chemical  indifference,  and  insulating  power  for 
electricity.  However,  compounds  possessing  to  a  great  ex- 
tent the  above-mentioned  properties  are  now  successfully 
produced,  and  may  for  many  purposes  be  substituted  for 
rubber.  By  the  invention  of  such  masses  great  service  has 
been  rendered,  especially  to  the  electrical  industry,  because 
many  of  them  possess  the  highly-important  property  of 
rubber,  namely,  the  power  of  insulation. 

The  rubber  substitutes  may  be  divided  into  two  groups  : 
Masses  containing  rubber,  but  only  in  subordinate  quantity, 
while  the  main  mass  consists  of  other  less  valuable  sub- 
stances ;  and  masses  which  contain  no  rubber  whatever,  but 
are  prepared  from  various  substances,  and  yield  a  product 
which  may  for  many  purposes  replace  rubber,  thus  repre- 
senting a  rubber  substitute  in  the  actual  sense  of  the  word. 
According  to  Steenstrup's  method,  a  material  which  may 
be  utilized  as  a  substitute  for  rubber  is  prepared  as  follows : 
Waste  rubber  is  dissolved  with  the  application  of  heat  in 
drying  oils.  The  resulting  solution  is  strongly  heated  and, 

(315) 


316  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

while  constantly  stirring,  a  current  of  air  is  conducted 
through  it,  till  a  cooled  sample  shows  the  proper  consistency. 
Since  the  actual  rubber  substitutes,  i.  e,,  masses  contain- 
ing no  rubber  whatever,  deserve  the  greatest  attention,  be- 
cause no  expensive  materials  have  to  be  used  in  their 
production,  they  being  on  the  contrary  prepared  from  sub- 
stances, large  quantities  of  which  are  always  at  disposal,  a 
more  detailed  description  of  them  will  here  be  given.  They 
are  prepared  by  a  peculiar  treatment  of  oils,  and  according 
to  their  mode  of  production  may  be  designated  :  1.  Oxi- 
dized oils.  2.  Sulphured  oils.  3.  Oils  treated  with  disul- 
phur  dichloride.  By  treatment  with  the  chemicals,  the 
oils,  in  all  cases,  undergo  such  far-reaching  chemical 
changes  that  they  cannot  be  called  changed  oils,  but  must 
be  designated  as  products  formed  from  the  oils.  The  gen- 
eral term  oil-rubber  has  been  applied  to  these  products,  but 
they  may  be  divided  into  several  subdivisions,  namely: 
Actual  oil-rubber,  vulcanized  oil,  andfactis. 

1  OIL-RUBBER. 

Certain  oils  possess  the  property  of  absorbing  in  the 
course  of  time,  when  exposed  to  the  air,  considerable  quan- 
tities of  oxygen,  becoming  thereby  thicker,  and  are  finally 
converted  into  quite  solid  masses,  which,  however,  retain 
always  a  certain  elasticity.  Such  oils  are  called  drying  oils, 
in  contra-distinction  to  non-drying  oils,  which  turn  rancid 
on  exposure  to  air,  but  remain  thinly-fluid.  The  best 
known  representative  of  the  drying  oils  is  linseed  oil,  and 
of  the  non-drying  oils,  olive  oil. 

By  raising  the  temperature  the  oxidizing  action  of  the 
oxygen  is  considerably  increased,  and  with  the  use  of 
higher  temperatures,  linseed  oil  may  in  a  comparatively 
short  time  be  completely  oxidized.  This  fact,  together 
with  the  powerful  oxidizing  action  of  nitric  acid,  is  ex- 
tensively made  use  of  in  preparing  oil-rubber. 

The  first  step  in  the  manufacture  of  oil-rubber  is  to  bring 


RUBBER    SUBSTITUTES.  317 

the  linseed  oil  into  large  boilers,  preferably  heated  by  gas 
supplied  from  a  generator-furnace,  instead  of  by  an  open 
fire.  With  the  use  of  generator-gas,  the  temperature  to 
which  the  boiler  is  to  be  heated  can  be  most  accurately 
regulated,  and  there  is  no  danger  of  its  contents  running 
over  or  igniting,  which  would  cause  considerable  loss. 

In  the  generator-furnace  furnishing  the  gas  lies  a  wrought 
iron  pipe,  one  end  of  which  is  connected  with  an  air-forcing 
pump,  while  the  other  end,  close  over  the  bottom  of  the 
boiler,  terminates  in  a  rose  resembling  that  of  a  watering 
pot. 

The  operation  is  commenced  by  heating  the  linseed  oil  in 
the  boiler  nearly  to  the  temperature  at  which  decomposi- 
tion commences,  but  without  ever  reaching  that  point. 
When  the  linseed  oil  commences  to  throw  out  thick  vapors 
and  gets  into  an  undulating  motion,  resembling  that  of  a 
boiling  fluid,  its  consistency  has  already  undergone  a  re- 
markable change.  While  before,  the  oil  would  run  down 
in  a  thin  stream  on  a  spatula  dipped  into  it,  it  now  shows 
quite  a  high  degree  of  viscosity,  and  runs  from  the  spatula 
in  viscous,  thick  drops. 

When  the  oil  has  reached  this  state,  the  air-pump  is  set 
to  work  and  a  current  of  hot  air  is  uninterruptedly  forced 
through  the  oil.  In  contact  with  the  hot  air  oxidation  pro- 
ceeds very  rapidly,  and  heating  for  three  to  five  hours  is 
generally  sufficient  for  the  conversion  of  the  oil  into  a 
viscous  mass. 

In  order  to  ascertain  whether  the  oil  has  been  sufficiently 
heated,  a  sample  is  taken  from  the  boiler  and  allowed  to 
cool  rapidly  upon  a  metal  plate.  The  drops  of  oil  should 
at  the  ordinary  temperature  congeal  to  the  consistency  of 
hardening  glue,  and  show  elasticity  when  pressed  with  the 
point  of  the  finger. 

When  the  sample  is  of  suitable  consistency,  the  oil  is 
brought  into  iron  vats  in  which  it  remains  till  cooled  to  the 
ordinary  temperature,  and  is  then  further  worked.  The  oil 


318  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

might  be  allowed  to  cool  in  the  boiler  itself,  but  this  would 
require  too  much  time,  and  besides  the  boiler  could  not  be 
immediately  used  for  a  fresh  operation. 

The  final  oxidation  of  the  oil  is  effected  by  treating  it 
with  nitric  acid,  the  quantity  of  acid  required  being  the 
smaller  the  further  the  oxidation  of  the  oil  in  the  boiler  has 
been  carried.  Hence,  a  fixed  proportion  of  oil  to  acid  can- 
not be  given,  and  the  quantity  of  the  latter  required  for  the 
contents  of  the  boiler  has  to  be  determined  by  an  experi- 
ment on  a  small  scale. 

The  thick  oil  is  brought  into  large  stoneware  or  porcelain 
dishes  which  will  bear  heating,  and  the  required  quantity  of 
nitric  acid  having  been  added,  the  mass  is  heated,  and 
frequently  stirred  with  a  glass  rod.  By  the  powerful  oxi- 
dizing action  of  the  nitric  acid,  the  oil  thickens  very  rapidly 
and  samples  have  to  be  repeatedly  taken.  When  a  sample 
cooled  to  the  ordinary  temperature  appears  quite  solid  and 
can  be  readily  kneaded  with  the  fingers,  the  action  of  the 
nitric  acid  is  finished.  It  is  of  importance  to  place  the 
dishes  in  which  the  thick  oil  is  to  be  heated  with  nitric 
acid  in  a  room  which  can  be  thoroughly  aired,  considerable 
quantities  of  nitric  oxide  being  evolved  by  the  action  of  the 
nitric  acid  upon  the  linseed  oil.  This  gas,  as  is  well  known, 
exerts  an  injurious  effect  upon  the  respiratory  organs,  and 
should,  therefore,  by  all  means  be  removed  from  the  work- 
room. 

When  reaction  is  complete,  the  mass  is  allowed  to  cool  to 
the  ordinary  temperature  in  the  dishes,  and  is  then  rolled 
into  thin  bands  by  passing  it  through  two  glass  rolls  very 
closely  set  together.  The  band  thus  formed  is  allowed  to 
drop  into  a  large  vessel  filled  with  warm  water,  the  greater 
portion  of  nitric  acid  adhering  to  it  being  thereby  removed. 
For  the  purpose  of  freeing  it  from  the  last  traces  of  acid,  it 
is  thoroughly  worked  in  a  large  vessel  containing  hot  soda 
solution. 

The  oil-rubber  obtained  in  this  manner  forms  a  brown, 


RUBBER    SUBSTITUTES.  319 

elastic  mass  possessing  quite  a  high  degree  of  elasticity.  It 
is  indifferent  towards  most  chemicals,  and  is  not  changed 
by  remaining  for  a  long  time  under  water.  It  dissolves 
with  ease  in  oil  of  turpentine,  and  this  behavior  may  be 
utilized  to  increase  its  elasticity,  or  to  incorporate  indif- 
ferent substances  with  it,  by  adding  small  quantities  of  oil 
of  turpentine  to  the  mass  while  it  is  being  worked  in  the 
rolls.  In  the  course  of  time,  oil-rubber  loses  some  of  its 
elasticity,  the  latter  decreasing  also  to  a  considerable  extent 
at  a  lower  temperature.  Old  oil-rubber  which  has  become 
hard,  may  however,  be  restored  by  cutting  it  up  into  small 
pieces,  bringing  the  latter  into  a  vessel,  sprinkling  oil  of 
turpentine  over  them,  and  closing  the  vessel  air-tight.  The 
mass  in  a  short  time  swells  up  in  the  oil  of  turpentine,  and 
by  kneading  can  be  made  into  a  uniform  substance  with 
nearly  the  same  properties  as  freshly-prepared  oil-rubber. 

Oil-rubber  may  for  many  purposes  be  used  as  an  excellent 
substitute  for  genuine  rubber.  Thus,  for  instance,  it  is  very 
well  adapted  for  cushions  for  the  support  of  rapidly-revolv- 
ing machinery  to  neutralize  the  shocks  to  which  its  parts 
are  exposed.  It  is,  however,  especially  suitable  as  an  in- 
sulating material  for  electric  lines,  and,  in  a  softened  state, 
is  much  used  for  covering  electric  wires. 

MANUFACTURE  ON  A  LARGE  SCALE  OF  OIL-RUBBER   BY  MEANS 
OF  THICK  OIL. 

In  the  manufacture  of  oil-rubber,  as  well  as  in  the  pro- 
duction of  other  materials  used  as  rubber  substitutes,  the 
linseed  oil  used  for  the  purpose  has  by  long-continued  heat- 
ing4)o  be  highly  oxidized  till  it  is  converted  into  a  viscous 
mass.  For  the  purpose  of  obtaining  such  a  mass,  the  lin- 
seed oil  has,  however,  to  be  heated  for  a  comparatively  long 
time  at  a  temperature  closely  approaching  that  at  which 
decomposition  begins. 

This  operation  is,  however,  not  only  expensive,  but  also 
to  a  certain  extent  dangerous — expensive  by  reason  of  the 


320 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


considerable  consumption  of  fuel,  and  dangerous  on  account 
of  the  ease  with  which  the  heated  oil  ignites,  and  of  the 
vapors  evolved  from  it,  which  attack  the  eyes  and  respi- 
ratory organs. 

Since  oxidation  can  evidently  take  place  only  where  the 
hot  oil  is  in  contact  with  air,  i.  e.,  on  the  surface,  when 
heating  is  effected  in  boilers,  oxidation  can,  of  course,  be 
accelerated  by  giving  the  oil  a  very  large  surface.  For 

FIG.  40. 


the  purpose  of  attaining  this  object  various  apparatuses 
have  been  constructed,  the  main  feature  of  which  consists 
in  that  the  oil  falls  down  in  the  form  of  a  spray,  and  is  met 
by  an  ascending  current  of  warm  air.  Fig.  40  shows  an 
apparatus  which  answers  these  demands. 

The  oil  to  be  worked  is  poured  through  the  aperture  0 
on  the  boiler-shaped  vessel  L,  and  0  is  then  closed.     The 


RUBBER    SUBSTITUTES.  321 

vessel  L  is  surrounded  by  a  jacket  M.  The  oil  is  heated 
by  opening  the  cock  Z),  and  introducing  steam  in  the  space 
between  L  and  M,  the  condensed  water  running  off  through 
E.  In  the  vessel  L  lies  a  pipe  rolled  into,  a  spiral,  which 
rises  free  in  the  centre  of  the  vessel,  and  is  covered  by  a 
sheet-iron  cap  H.  The  end  V  of  the  spiral  pipe  projecting 
from  L  is  connected  with  a  ventilator  which  constantly 
forces  a  slow  current  of  air  through  the  pipe  8.  In  its  pas- 
sage through  this  pipe,  the  air  is  heated  and  escapes  at  H. 
Upon  the  vessel  L  sits  a  box  several  meters  high.  The 
sides  of  this  vessel  are  of  glass,  so  that  the  oil  falling  down 
into  the  box,  is  exposed  to  the  action  of  the  warm  current 
of  air,  as  well  as  to  that  of  light,  its  oxidation  being  in  a 
very  short  time  effected  by  both  of  these  factors.  The  oil 
is  constantly  sucked  by  a  pump  from  L,  and  forced  through 
the  pipe  R  into  the  reservoir  B.  The  latter  is  furnished 
with  a  perforated  bottom,  so  that  the  oil  divided  into  fine 
drops  falls  free  through  the  space  (7,  and  meets  the  ascend- 
ing warm  current  of  air,  which  escapes  from  the  box  GG 
through  the  apertures  at  T. 

As  a  rule,  two  to  three  hours  suffice  to  thicken  the  oil  in 
this  apparatus  to  the  same  consistency  it  would  otherwise 
acquire  by  long-continued  heating  to  a  very  high  tempera- 
ture. In  addition,  this  mode  of  preparing  thick  oil,  has 
the  advantage  of  the  product  retaining  its  light  color,  while 
oil  thickened  by  long-continued  heating  always  acquires  a 
dark-brown  color. 

The  thick  oil  is  worked  as  follows :  It  is  brought  into  a 
large  stoneware  or  porcelain  dish,  and  nitric  acid  diluted 
with  about  twice  its  volume  of  water  having  been  poured 
over  it,  the  whole  is  heated  to  the  boiling  point.  The 
linseed  oil  mass  becomes  thereby  constantly  thicker,  and 
finally  solid.  Boiling  is  continued  until  a  sample,  when 
cold,  scarcely  takes  the  impress  of  a  finger  nail. 

When  this  is  the  case,  the  mass  is  taken  from  the  nitric 
acid  and,  for  the  removal  of  the  last  traces  of  the  latter,  is 
21 


322  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

repeatedly  boiled  in  water.  If  the  mass  is  to  be  brought 
into  any  particular  shape,  it  need  only  be  placed  in  hot 
water,  becoming  thereby  perfectly  plastic  and,  on  cooling, 
reacquires  its  original  solidity  and  elasticity. 

Oil-rubber  may  be  applied  to  various  purposes,  and  in 
many  cases  serve  as  a  substitute  for  rubber.  Its  use  for 
securing  large  panes  of  glass  in  frames  might  prove  of 
special  importance  and  value.  While  ordinary  putty,  in 
the  course  of  time,  becomes  hard  as  stone,  oil-rubber  always 
remains  elastic,  and  allows  of  the  expansion  of  the  glass  in 
sudden  changes  of  temperature,  cracking  of  the  glass  being 
thus  prevented.  Oil-rubber  being  quite  tenacious,  it  might 
also  be  suitable  for  tires  for  heavy  wagons  and  motor 
wagons.  When  softened  by  heating  it  may  readily  be 
rolled  out  into  thin  plates  which,  when  applied  by  pressure 
to  tissues,  adhere  firmly  to  them  and  render  them  water- 
proof. 

PACTIS    MASSES. 

Under  the  name  factis,  masses  have  for  some  time  been 
brought  into  commerce  from  England,  which  may  be  used 
as  a  direct  substitute  for  rubber,  as  well  as  an  addition  to 
pure  rubber,  the  essential  properties  of  the  latter  being  not 
perceptibly  impaired  by  the  admixture  of  quite  a  consider- 
able quantity  of  them.  Factis  masses  vary  very  much  in 
appearance,  some  of  them  being  of  a  white,  or  only  slightly 
yellowish,  color,  while  others  are  more  or  less  dark  brown 
to  black.  Their  consistency  is  similar  to  that  of  quite 
highly  vulcanized  rubber. 

The  result,  of  a  chemical  examination  makes  it  quite  cer- 
tain that  these  masses  are  prepared  from  a  fat  oil,  and  in 
all  of  them  considerable  quantities  of  sulphur  were  found, 
while  some  of  them  also  contained  considerable  quantities 
of  chlorine.  Based  upon  these  examinations,  it  was  sur- 
mised that  the  factis  masses  are  prepared  either  from  sul- 
phured oils  alone,  or  that  they  may  also  be  produced  by  a 


RUBBER    SUBSTITUTES.  323 

reaction  of  disulphur  dichloride  upon  fat  oils.  Both  these 
surmises  proved  correct,  and  the  production  of  factis  equal, 
as  regards  properties,  to  the  English  article,  has  been  suc- 
cessfully accomplished. 

SULPHURED    OILS    (BROWN    AND    BLACK    FACTIs). 

Drying  as  well  as  non-drying  fat  oils,  when  heated  to- 
gether with  sulphur  dissolve  a  considerable  quantity  of  the 
latter,  being  thereby  converted  into  viscous  masses  of  a 
dark  color.  If  the  oil,  previous  to  the  introduction  of  the 
sulphur,  be  highly  oxidized,  solid,  tenacious,  and,  up  to  a 
certain  degree,  elastic  masses  of  a  dark  brown  to  black 
color  are  obtained. 

Every  kind  of  fat  oil  may  be  used  for  the  production  of 
such  masses,  though  castor  oil  and  rape  oil  are  said  to  be 
most  suitable  for  the  purpose.  The  oils  may  be  used  in 
the  crude  (unrefined)  state,  the  admixed  foreign  substances, 
such  as  mucilage,  albumen,  etc.,  being  separated  during  the 
manipulation. 

A  weighed  quantity  of  oil  is  brought  into  a  capacious 
boiler  and  quickly  heated  to  about  392°  F.  The  oil  rising 
very  much  in  the  boiler,  the  latter  should  only  be  filled  at 
the  utmost  two-thirds  full.  By  heating,  considerable  quan- 
tities of  frothy  curd  are  separated  upon  the  surface  of  the 
oil  and  have  to  be  removed,  so  that  the  oil  appears  as  a 
lustrous,  black  mass.  During  the  process  of  heating  a  cur- 
rent of  hot  air  is  forced  through  the  oil  till  a  cooled  sample 
shows  a  considerable  degree  of  viscosity. 

The  sulphur  to  be  used  should  be  perfectly  free  from  sul- 
phurous acid.  Hence,  flowers  of  sulphur  must  previously 
be  thoroughly  washed  and  again  dried,  and  roll-sulphur,  if 
used,  has  to  be  reduced  to  a  fine  powder. 

Five  parts  of  oil  to  1  part  of  sulphur  are  used.  An  ex- 
cess of  the  latter  should  be  avoided,  as  it  would  not  be  dis- 
solved in  the  mass,  but  simply  distributed  in  it.  The 
sulphur  powder  is  allowed  to  run  without  interruption  in  a 


324  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

thin  jet  into  the  hot  oil,  the  latter  being  kept  in  constant 
motion  by  means  of  a  paddle,  or  what  is  better,  by  a  me- 
chanical stirrer.  Shortly  after  the  introduction  of  the 
sulphur,  the  mass  commences  to  rise  very  much,  and  a  too 
vigorous  reaction  has  to  be  prevented  by  moderating  the 
fire  and  by  vigorous  stirring. 

The  operation  may  be  considered  finished  when  a  sample 
of  the  mass  dropped  upon  a  cold  sheet  of  metal  congeals  to 
a  solid  body.  The  contents  of  the  boiler  are  then  brought 
into  shallow,  prismatic  sheet-iron  vessels,  and  allowed  to 
congeal.  The  mass,  while  still  warm,  is  taken  from  the 
vessels,  and  made  uniform  by  rolling.  It  is  finally  again 
softened  by  the  application  of  heat,  and  made  into  blocks 
by  pressure. 

This  oil-rubber  is  less  often  used  by  itself,  but  finds 
considerable  application  as  an  addition  to  rubber  for  the 
manufacture  of  cheaper  articles. 

Several  other  substances,  chiefly  asphalt  and  vaseline, 
are  frequently  added  to  oil-rubber  masses,  which  are  not 
to  be  mixed  with  pure  rubber.  When  vaseline  is  to  be 
used,  it  is  added  to  the  oil  when  the  latter  is  heated,  and, 
when  melted,  intimately  mixed  with  it  by  stirring.  The 
mixture  is  then  treated  with  hot  air  in  the  above-described 
manner.  If  asphalt  is  to  be  incorporated  with  the  mass, 
it  is  added  in  small  pieces  to  the  hot  oil  and  intimately 
mixed  with  it  by  stirring.  A  quantity  of  asphalt  equal  to 
10  per  cent,  of  the  oil  may  be  added. 

Masses  of  a  dark  brown  to  black  color  are  finally  obtained. 
They  may  be  used  by  themselves  as  an  insulating  material 
for  electrical  purposes,  though  they  are  chiefly  utilized  as 
an  addition  to  rubber. 

VULCANIZED    OIL. 

The  product  to  which   this   term   has  been    applied   is 
formed  by  the  action  of  disulphur  dichloride  upon  oils. 
If  a  fat  oil,  for  instance,  rape  oil,  be  mixed  with  a  quan- 


RUBBER    SUBSTITUTES.  325 

tity  of  disulphur  dichloride  equal  to  TV  of  its  volume,  the 
latter  at  first  dissolves  without  perceptible  change.  How- 
ever, a  very  energetic  reaction  soon  sets  in.  The  mass  be- 
comes heated  to  between  131°  and  140°  F.,  evolves  vapors 
of  hydrochloric  acid,  and  is  converted  into  a  solid  trans- 
parent substance  which,  when  brought  into  water,  becomes 
opaque  and  possesses  the  consistency  of  rubber. 

While  oil-rubber  is  soluble  in  oil  of  turpentine,  alkalies, 
etc.,  vulcanized  oil  is  distinguished  by  its  great  indifference 
towards  the  action  of  chemicals,  being  not  affected  even 
by  boiling  alkalies  and  acids* 

This  indifference  may  be  utilized  for  the  preparation  of  a 
varnish  possessing  great  power  of  resisting  the  action  of 
chemicals.  Dissolve  linseed  oil  in  a  quantity  of  carbon 
disulphide  equal  to  30  or  40  times  its  weight,  add  disulphur 
dichloride  equal  to  TV  of  the  weight  of  linseed  oil,  and  use 
the  mass  for  coating  wood,  tissues,  metals,  etc.  The  coat 
becomes  dry  in  a  few  days,  when  the  article  appears  as 
having  been  coated  with  vulcanized  oil. 

WHITE    FACTIS. 

This  product  occurs  in  the  form  of  yellowish-white  elastic 
masses  possessing  a  slight  odor  of  oil.  It  is  not  attacked 
by  dilute  alkalies  and  acids.  It  is  produced  by  the  action 
of  disulphur  dichloride  upon  fat  oils,  and  it  is  a  remarkable 
fact  that  exactly  determined  quantities  of  disulphur  di- 
chloride have  to  be  used.  If  smaller  quantities  of  it  are 
taken  the  oils  are  only  converted  into  smeary,  gelatinous 
masses,  which  never  become  solid. 

R.  Henriquez  has  devoted  much  time  to  the  investigation 
of  rubber  substitutes,  and  to  him  we  are  indebted  for  the 
correct  method  of  preparing  white  factis. 

If  a  fat  oil  be  compounded  with  a  sufficiently  large  quan- 
tity of  disulphur  dichloride,  a  mixture  of  the  two  fluids  is 
immediately  effected.  However,  the  fluid  in  a  short  time 
becomes  heated,  rises  in  bubbles,  evolves  vapors,  and  is  in 


326 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


a  short  time  converted  into  a  pale-yellow,  solid  substance, 
showing  scarcely  any  stickiness  or  elasticity.  The  vapors 
evolved  consist  chiefly  of  disulphur  dichloride  mixed  with 
small  quantities  of  hydrochloric  acid  and  sulphurous  acid. 
By  exposure  to  the  air  a  small  quantity  of  disulphur  di- 
chloride evaporates,  and  the  mass  then  possesses  all  the 
properties  of  the  English  product. 

Dilution  of  the  disulphur  dichloride  with  benzine  or 
carbon  disulphide  causes  the  reaction  to  run  its  course  less 
violently,  but  the  final  product  is  the  same  as  with  the  use 
of  pure  disulphur  dichloride. , 

Drying,  as  well  as  non-drying  oils,  may  be  utilized  for 
the  production  of  factis,  and,  strange  to  say,  the  quantities 
of  disulphur  dichloride  required  for  the  conversion  of  the 
different  oils  into  factis  vary  very  much.  As  shown  by 
comparative  experiments,  oxidized  oils,  i.  e.y  oils  which 
have  been  thickened  by  blowing  hot  air  through  them,  re- 
quire far  less  disulphur  dichloride  for  the  formation  of 
factis  than  oils  not  treated  in  this  manner.  Oxidized  cot- 
ton oil  yielded  a  good  quality  of  factis  with  20  per  cent,  of 
its  weight  of  disulphur  dichloride,  while  40  per  cent,  was 
required  for  non-oxidized  oil.  The  figures  given  below  for 
some  of  the  oils  most  frequently  used  for  the  production  of 
factis,  as  compiled  by  Henriquez,  refer  to  non-oxidized  oils  : 


100  parts                                                congeal 

Linseed  oil    .    .  w 

th  30  parts  disulphur  dichloride 

but  not  with  25  parts. 

Poppy  oil  .    .    . 

35     " 

it 

1.1     ti 

30     " 

Rape  oil    ... 

25     k< 

" 

"     " 

20     " 

Cotton  oil  .    .    . 

45     "           -.' 

* 

K         11 

40     " 

Olive  oil    .    .    . 

25     "            ' 

i  i 

11         it 

20    " 

Castor  oil  .    .    . 

20     "        .    « 

« 

11         <l 

18    " 

The  manner  of  preparing  factis  on  a  large  scale  is  to 
some  extent  indicated  by  what  has  been  said  above.  Di- 
sulphur dichloride  being  an  expensive  article,  it  would  for 
economical  reasons  seem  advisable  to  work  with  oxidized 
oils,  they  requiring  less  of  it  than  non-oxidized  oils. 


RUBBER    SUBSTITUTES.  327 

Special  vessels  of  a  shape  suitable  for  the  purpose  should 
be  used  for  the  oxidation  of  the  oil,  a  shallow  pan,  upon  the 
bottom  of  which  lies  a  bent  pipe  furnished  with  numerous 
narrow  apertures  by  means  of  which  hot  air  is  blown 
through  the  oil  being  very  suitable.  The  crude  oil  having 
been  rapidly  Heated  to  between  392°  and  464°  F.,  and  the 
scum  removed  from  the  surface,  a  current  of  hot  air  is 
blown  through  it,  whereby  the  temperature  may  be  in- 
creased to  about  ^72°  F.  When  the  oil  is  sufficiently  thick- 
ened, it  is  allowed  to  run  in  a  thin  jet  into  the  reservoir, 
and  to  cool  in  it  to  the  ordinary  temperature.  The  prepar- 
ation of  factis  is,  as  a  rule,  effected  in  deep  boilers  enam- 
elled inside,  having  each  a  capacity  of  up  to  66  gallons. 
However,  only  about  110  Ibs.  of  oil  should  at  one  time  be 
worked,  since  the  oil  on  coming  in  contact  with  the  disul- 
phur  dichloride  rises  in  the  boiler,  and  with  larger  quanti- 
ties, reaction  would  be  so  violent  that  running-over  of  the 
mass  could  scarcely  be  avoided.  The  boilers  should  be  so 
arranged  in  the  workroom  that  over  each  of  -them  is  fixed 
a  hood  of  boards  for  catching  the  vapors,  the  latter  being 
rapidly  removed  by  means  of  a  powerful  ventilator.  This 
precaution  is  absolutely  necessary,  as  disulphur  dichloride 
is  very  poisonous  and  attacks  especially  the  respiratory 
organs. 

The  weighed  quantity  of  oil  is  brought  into  the  boiler 
and  by  vigorous  stirring  set  in  a  rapid  rotatory  motion, 
when  the  required  quantity  of.  disulphur  dichloride  is  al- 
lowed to  run  in,  stirring  being  continued  so  long  as  the 
consistency  of  the  mass  will  permit.  The  commencement 
of  the  reaction  is  indicated  by  the  appearance  of  white 
vapors,  and  the  end  of  it,  by  the  cessation  of  the  evolution 
of  vapors,  when  the  mass  must  at  the  same  time  have  be- 
come solid. 

The  mass  is  now  quickly  taken  from  the  boiler  and  rolled 
out  into  thin  bands.  The  latter  are  placed  on  nets  made 
of  twine  stretched  in  frames,  where  they  remain  until  the 


328  CELLULOSE,  AND    CELLULOSE    PRODUCTS. 

odor  of  disulphur  dichloride  has  entirely  disappeared.  The 
mass  should  be  entirely  odorless,  or  only  show  a  slight  odor 
of  oil.  It  should  not  yield  soluble  bodies  of  any  kind  to 
water.  By  heating,  it  must  become  soft  and  plastic,  and 
allow  of  its  being  rolled  or  pressed  into  any  desired  shape. 
By  themselves,  factis  masses  prepared  from  oils  with  disul- 
phur dichloride  may  be  very  well  used  for  insulating  elec- 
tric lines,  but  their  principal  application  is  as  admixture  to 
genuine  rubber,  it  being  thus  possible  to  bring  into  com- 
merce cheaper  rubber  articles.  The  addition  of  factis  is 
generally  effected  while  working  the  crude  rubber  in  the 
kneading  machine,  the  whole  being  worked  until  a  thor- 
oughly homogeneous  mass  has  been  formed,  in  which  the 
particles  of  rubber  cannot  be  distinguished  from  the  par- 
ticles of  factis. 

SULPHURETTED    HYDRO-CELLULOSE    AS    RUBBER     SUBSTITUTE. 

A  substitute  for  pure  rubber,  which  may  be  prepared 
with  the  use  of  sulphuretted  hydro-cellulose,  discovered  by 
Sthamer,  deserves  special  attention.  This  compound  is 
obtained  by  bringing  440  Ibs.  of  finely  ground  hydro-cellu- 
lose into  a  sufficient  quantity  of  hydrochloric  acid  of  24°  Be., 
at  the  ordinary  temperature,  so  that  a  thin  paste  is  formed 
and  all  is  dissolved.  To  the  solution  154  Ibs.  of  disulphur 
dichloride  are  added,  with  vigorous  stirring.  The  fluid 
after  some  time  becomes  turbid  and  acquires  a  gray-yellow 
color.  By  bringing  later  on  the  entire  mass  into  cold 
water,  the  sulphuretted  hydro-cellulose  in  the  form  of  a 
mass,  insoluble  in  water,  separates  upon  the  bottom  of  the 
vessel.  It  is  brought  upon  a  filter  to  recover  as  far  as  pos- 
sible the  hydrochloric  acid,  the  acid  running  off  first,  still 
showing  a  strength  of  20°  Be.  Later  on  the  mass  is  washed 
with  water  until  the  fluid  running  off  no  longer  shows  an 
acid  reaction. 

Pure  sulpho-hydrocellulose  is  very  indifferent  towards 
chemicals,  and  cannot  be  dissolved  in  any  known  solvent. 


RUBBER    SUBSTITUTES.  329 

It  appears  that  the  combination  may  to  great  advantage  be 
utilized  in  the  rubber  industry  for  the  preparation  of  a  very 
good,  and  at  the  same  time  cheap,  substitute  for  rubber. 
By  heating  the  sulpho-hydrocellulose  together  with  rubber, 
it  is  decomposed,  and  yields  the  entire  quantity  of  sulphur 
contained  in  it  to  the  rubber,  the  latter  becoming  thereby 
vulcanized.  The  liberated  cellulose  at  the  same  time  en- 
ters into  chemical  combination  with  the  entire  mass,  the 
result  being  a  thoroughly  uniform  body. 

By  mixing  sulpho-lrydrocellulose — about  60  per  cent. — 
with  inferior  qualities  of  rubber,  and  heating,  more  or  less 
porous  masses  are  obtained,  from  which  tubes  and  plates 
suitable  for  insulating  electric  lines  may  be  formed.  In  a 
moist  state,  sulpho-hydrocellulose  may  also  be  pressed  in 
moulds.  The  articles  thus  obtained,  when  dry,  are  very 
hard,  of  a  greasy  feel,  slight  lustre,  and  should  possess  the 
color  of  wood. 

PREPARATION    OF    DISULPHUR    BICHLORIDE. 

Large  quantities  of  disulphur  dichloride  are  used  in  the 
manufacture  of  vulcanized  oil  and  factis  masses,  and  being 
rather  expensive,  it  is  of  advantage  to  manufacturers  of 
these  materials  to  prepare  it  themselves. 

Disulphur  dichloride  is  obtained  by  heating  sulphur  and 
passing  dry  chlorine  gas  over  it.  The  sulphur  melts,  and 
the  two  elements  unite  to  a  volatile  combination  of  the 
composition  S2C12.  For  the  preparation  of  large  quantities 
of  disulphur  dichloride,  the  apparatus  shown  in  Fig.  41 
may  be  used.  It  consists  of  the  glazed  stoneware  muffle 
M,  placed  in  the  furnace  F,  so  as  to  be  uniformly  heated  on 
every  side.  On  top  of  the  muffle  is  a  pipe  R,  projecting 
above  the  furnace,  through  which  the  sulphur  to  be  worked 
is  introduced.  During  the  operation  this  pipe  is  closed  by 
a  lid  luted  with  clay.  The  pipe  (7,  the  end  of  which  is 
slightly  bent  downwards,  connects  with  the  apparatus  for 
the  development  of  the  chlorine  gas,  and  enters  the  muffle 


330 


CELLULOSE,  AND    CELLULOSE    PRODUCTS. 


through  the  back  wall.  The  pipe  D  placed  in  the  front 
wall  of  the  muffle  terminates  in  a  cooling  coil,  in  which  the 
vapors  evolved  in  the  muffle  are  condensed. 

The  operation  commences  with  melting  the  sulphur  in 
the  muffle  and  heating  it  to  between  320°  and  338°  F., 
when  the  chlorine  gas  is  introduced.  The  latter,  before 
reaching  the  muffle,  must  pass  through  a  vessel  filled  with 
concentrated  sulphuric  acid,  in  order  to  free  it  from  every 
trace  of  moisture.  The  fire  as  well  as  the  current  of 
chlorine  gas  is  so  regulated  that  the  crude  disulphur  di- 
chloride  runs  off  in  a  uniform  stream  from  the  cooling  coil. 

FIG.  41. 


The  fluid  obtained  in  this  manner  is  by  no  means  a  pure 
product,  it  containing  considerable  quantities  of  sulphur  in 
solution.  However,  it  may  be  directly  used  for  the  prepar- 
ation of  factis,  the  presence  of  sulphur  in  it  not  having 
proved  detrimental. 

For  the  purpose  of  obtaining  pure  disulphur  dichloride, 
such  as  is  required  for  experiments,  the  crude  product  is 
repeatedly  distilled  from  glass  retorts  until  a  distillate  boil- 
ing at  266°  F.  and  of  specific  gravity  1.6802,  is  obtained. 
The  pure  disulphur  dichloride  thus  prepared  is  an  oily,  red- 
yellow  liquid,  fuming  strongly  in  the  air,  it  being,  by  the 


RUBBER    SUBSTITUTES.  331 

moisture  contained  in  the  air,  immediately  decomposed  to 
sulphur  dioxide,  sulphurous  acid,  sulphur  and  hydrochloric 
acid.  The  vessels  serving  for  storing  disulphur  dichloride 
must,  therefore,  be  carefully  dried  and  closed  air-tight  with 
ground-glass  stoppers. 

Great  care  should  be  exercised  in  handling  disulphur  di- 
chloride, the  mucous  membranes  of  the  eyes,  nose  and 
respiratory  organs  being  violently  attacked  by  the  vapors 
of  it.  The  best  protection  from  the  vapors  for  the  work- 
man engaged  in  mixing  the  disulphur  dichloride  with  the 
oil,  is  a  head-piece  or  mask,  air  from  the  outside  being  in- 
troduced through  a  hose  connected  with  an  air-pump. 


OF  THE 

UNIVERSITY 

OF 

'  v     _* 


INDEX. 


ABADIE'S  grinding   machine,  32, 
33 
Acetic  acid,  126 

action  of,  upon  cellulose,  13 
concentrated,  use  of,  for  dis- 
solving nitro-cellulose,  223 
Acetone,  treatment  of  nitro-cellulose 

with,  189 
Acetyl-cellulose,  202,  203 

derivative  of  cellulose,  202,  203 
lactic  acid,  126 
Acid  for  nitration,  175-177 

sulphites  of  alkalies  and  alkaline 
earths,  action   of,   upon   cellu- 
lose, 13 
Acids,  behavior  of  cellulose  towards, 

11-14 

storage  of,  176 
After-nitration,  181 
Alcohol,  absolute,  boiling-point  of,  274 
and  sugar,   production   of,    from 

wood  cellulose,  93-107 
behavior  of  celluloid  towards,  282 
from  beech,  96 
cellulose,  12 
wood,  12 

apparatus  for  the  produc- 
tion of,  97 
Classen's    process,    102- 

107 

value  of,  102 
nature  of  wood  to  be  worked  for, 

96-98 

solidification  of,  203,  204 
varieties  of  wood  suitable  for  the 

production  of,  97 
yield  of,  from  wood,  107 
Alcoholic  camphor  solution,  prepara- 
tion of  celluloid  with,  269,  270 
Alkalies,  behavior  of  cellulose  towards, 

14,15 
caustic,    treatment    of    cellulose 

with,  14,  15 
Aloe,  6 

Ammonia,  replacing  the  soda  in  vis- 
cose by,  131 
Ammonium  sulphate,  recovery  of,  241 

(333) 


Ammonium      sulphide,      denitration 

with,  220 
viscose,  use  of  for  sizing  paper, 

139,  140 
Amyloid,  12 

Animals,  occurrence  of  cellulose  in,  2 
Antimony  pentasulphide,  309 
Aqua  regia,  use  of,  for  the  disintegra- 
tion of  the  wood-fibre,  51 
Armor,  celluloid  lacquer  for.  303 
Artificial  flowers,  celluloid  lacquer  for, 

305 

horse-hair,  244,  245 
rubber,  197-200 
silk,  171,  205-228 

according  to  M.  Fremery  and 

J.  Urban,  242-244 
apparatus  for  spinning,  217- 

219 

bleaching  of,  221 
BronnerVs,  236,  237 
Chardonnet,  209-222 
colored,  preparation  of,  221, 

222 
denitration  of,  220,  221,  225- 

228 

Du  Viviens,  222-224 
industry,  historical   develop- 
ment of,  207-209 
Lehner's,  224,  225 
Miller's,  253,  254 
Pauly's,  230-236 
Peit's,  227 

Art  objects  from  celluloid,  300 
Asbestus-felt  filtering  plates,  233 


BACHET  and   Machard's  method, 
51,  52,  95 

Balenite,  composition  of,  312 
Bark,  machine  for  removal  of,  24,  25 
Battery  for  lixiviation,  57 
Beater,  reduction  of  gun-cotton  in  the, 

184, 185 

Beech,  production  of  alcohol  from,  96 
steaming  of,  43,  44 
yield  of  cellulose  from,  59 
Belts  for  machines,  150 


334 


INDEX. 


Berlin-blue  on  celluloid,  286 

Bevan,  Beadle  and  Cross,  invention  of 

viscose  and  viscoid  by,  119 
Billiard  balls,  159 
Birch,  yield  of  cellulose  from,  59 
Black  factis,  323,  324 

on  celluloid,  286,  287 
Bleaching  agents  for  pulp,  43 

artificial  silk,  221 
Blue  on  celluloid,  286 

vitriol,  237 
Board  machine,  40 
Boards  from  steamed  wood-pulp,  47,  48 

preparation  of,  40 
Boiler  for  boiling  straw,  76,  77 

wood  with  lye,  67,  68 

Sinclair's,  54,  55 
Boiling  process,  lingerer's,  55 

wood  under  pressure,  98,  99 
Boll  of  cotton,  4 

Bronnert's  artificial  silk,  236,  237 
Brown  factis,  323,  324 

on  celluloid,  286 
Butts,  use  of,  78 

CADOKET'S  method   of  preparing 
artificial  silk,  208 
Calcium  bisulphite,  preparation  of,  61 

test  for,  69,  70 

Camphor    and    collodion-cotton,    ap- 
paratus for  dissolving,  273 
celluloid  masses  without  an  addi- 
tion of,  306-308 
mixture  of,  with  collodion-cotton, 

2.67 
solution,  alcoholic,  preparation  of 

celluloid  with,  269,  270 
substitutes  for,  307,  308 
Cane  heads  from  celluloid,  290 
Carbon  disulphide,  126 

and    soda-lye,    proportion 

between,  127 
protection  of  the  workmen 

from  the  vapors  of,  148 
recovery  of,  1 28,  148 
use  of,  in  the  preparation 
of  viscose  and  viscoid,  119 
Carton  pierre,  16 
Castor  oil,  316 

addition  of,  to  nitro-cellulose, 

197 

Celloidin,  194 
Celluloid,  17,  263-308 

admixture  of  foreign  bodies  with, 

268 
apparatus  for  the  preparation  of, 

267 

articles,  moulding  of,  293-295 
pictures  on,  287-289 


Celluloid,  artificial  flowers  of,  152 

behavior  of,  towards  solvents,  282 
chemical  nature  of,  263 
cliches  from,  295,  296 
collars  and  cuffs,  297,  298 
coloring  of,  284-287 

with  cinnabar,  299 
combs,  manufacture  of,  295 
constituents  of,  268 
constitution  of,  263,  264 
drying  chamber  for,  279,  280 
dry   method  for  the  preparation 

of.  265 

elasticity  of,  282,  283 
films  of,  153 

for  dentist's  use,  298,  299 
for  surgical  purposes,  282 
inflammability  of,  281,  282 
joining  two  pieces  of,  294,  295 
lacquer,  302-306 

colored,  305 
masses,    heating    apparatus    for, 

293,  294 
without   an   addition   of 

camphor,  306-308 
mechanical  manipulation  of,  283, 

284 
methods  for  the  preparation  of, 

263,  264 
mixing  of,  with  filling  materials, 

290,  291 

mosaics,  301,  302 
physical  properties  of,  282 
plasticity  of,  281 
-plate,  preparation  of  for  printing, 

287 
preparation  of,  according  to  Hyatt, 

266-268 

of,  according  to  Mag- 
nus, 270,  271 
of,  according  to  Tribou- 
illet  and  Besancele, 
268,  269 

of,  with  alcoholic  cam- 
phor solution,  269, 
270 

of,    with    recovery   of 
the  solvent,  271-279 
principal  requisite  for  the  manu- 
facture of,  265 
printing  on,  287-289 
properties  of,  280-283 
rolling  of,  280,  283,  284 
shaping  of,  by  pressing,  295 
solid,  preparation  of,  277-279 
stamps,  296 
trays  for  the  solidification  of,  275, 

276 
tubes,  294 


INDEX. 


335 


Celluloid,    wet  methods   for   the  pre- 
paration of.  265 
with  filling  materials,  289-293 

incrustations,  300 
working  of,  283,  284 
Cellulose,  1-21 

acetic  ester,  200-203 

acetyl  derivative  of,  202,  203 

alcohol  from,  12 

and     caustic    soda,    quantitative 

proportions  of,  1 22 
nitro-cellulose    silks,    differ- 
ence between,  261 
soda,  combination  of,  119 
artificial  silk  and  lustra-cellulose, 

229-245 

behavior  of,  at  an  increased  tem- 
perature, 15. 16 
towards  acids,  11-14 
alkalies,  14,  15 
water,  8,  9 
black  particles  in,  72 
bleaching  of,  239,  240 
brown  bundles  of  fibre  in,  72 
butyric  ester,  203 
chemically  pure,  preparation  of, 

from  cotton,  6 
combinations  formed  by  the  action 

of  nitric  acid  upon,  161 
comminution  of,  122 
conversion    of,   into   fermentable 

sugar,  17 
defects  of,  and  their  removal,  72, 

73 

destructive  distillation  of,  15 
digestibility  of,  7 
dinitrate.  195 
distribution  of,  1 
effect  of  sulphuric  acid  on,  82 
esters,  200-204 
filtering  plates,  249 
formula  of,  6 
for    the   preparation   of    viscose, 

121,  122 

from  straw,  18,  19,  75-78 
wood, 3 

preparation  of,  50-81 
principal    point    in   the 
preparation  of,  50,  51 
hexanitrate,  194 
historical  development  of  the  pro 

d  action  of,  20,  21 
industrial  uses  of,  16,  17 
iron  in,  73 
occurrence  of,  2,  3 
pen  tan  it  rate,  194 
percentage  composition  of,  7 
preparation  of,  by  means  of  soda, 
52-59 


Cellulose,  preparation  of,  by  means  of 
sodium  sulphite,  58, 59 
of,  from  straw,  2,  3 
of  oxalic  acid  from,  108- 

118 
of,  with  the  assistance  of 

sulphites,  59-73 
of,  with  the  assistance  of 
the     electric    current, 

73-75 
production  of,  17-21 

of  sugar  and   alcohol   from, 

93-107 

properties  of,  6,  7 
pure,  from  viscose,  246 
readily  soluble,  preparation  of,  240 
separation  of,  234 
silk,  206 

small,  lustrous  crystals  in,  72,  73 
solubility  of,  78 
solvents  for,  8,  229 
sources  of,  17,  18 
sulphocarbonate,  126,  127 

chemically  pure,  preparation 

of,  138 
uses  of,  16 

tetra-acetate,  200-203 
tetra-butyrate.  203 
tetranitrate,  194 
threads,  229-245 

advantages  of,  229 
drying  of.  235 
transformation  of,  7 
treatment  of,  with  caustic  alkalies, 

14,  15 

trinitrate,  195 

-vessels,   change    of,    into    wood- 
vessels,  1 
vulcanized,  90-92 
washing  of,  235 
the,  70,  71 
white  pieces   not  converted  into 

fibre  in,  72 

yellowish  or  brownish  color  of.  72 
yield  of,  59 
Centrifugal   apparatus   for    nitration, 

181,  182 

Chamber  acid,  84 
Chardonnet  artificial  silk,  209-228 
M.  de.,  apparatus  for  the  prepa- 
ration of  artificial  silk  by, 
217-219 

original  patent  of,  209,  210 
results    of   comparative    ex- 
periments by,  212,  213 
suggestion  of   artificial    silk 

by,  207 

j  Chemical  wood-pulp,  preparation  of, 
50-81 


336 


INDEX. 


Chemicals  and  wood .  consumption  of, 

59 

Chloride  of  lime,  bleaching  with,  77 
Chlorine,  disintegration  of  wood  by, 

106 

Chromium  glue,  preparation  of,  89,  90 
Cinnabar,  coloring  celluloid  with,  299 
Citric  acid,  action  of,  upon  cellulose,  13 
Classen's  process  for  the  production  of  | 

alcohol  from  wood,  102-107 
Cliches  from  celluloid,  295,  296 
Cloth-printing,  viscose  in,  142,  143 
Coal-tar  pitch,  309,  310 
Cog  wheels  from  viscoid,  160 
Collars  and  cuffs  from  celluloid,  297, 

298 

Collector  for  threads,  234 
Collodion,  193 

cotton,  166,  177 
acids  for,  190 
actual,  169 
and  camphor,  apparatus  for 

dissolving,  273 
drying  of,  272,  273 
dry,  solution  of,  271 
for  the  manufacture  of  textile 

threads,  190 
from  tissue  paper,  192 
mixture  of  camphor  with,  267 
neutralization  of,  196 
nitration  for  the  production 

of,  191 
or  soluble  gun-cotton,   190- 

192 

preparation  of,  265,  266 
solubility  of,  192,  196 
solution  of,  196 
sources  of,  271,  272 
test  for  the  solubility  of,  265 
testing  the  solubility  of,  272 
uniformity  of,  191 
for  photographic  purposes,  193- 

196 
mixture  of  coloring  matter  with, 

221,  222 
silk,  206 

solution,  filtering  of,  214 
preparation  of,  213-215 
storage  of,  196 
solvent  for,  214 
spinning  the,  215-217 
Coloring  celluloid,  284-287 

filled  celluloid  masses,  291 
Combs,  celluloid,  manufacture  of,  295 
Copper-plate     engravings,     celluloid 

lacquer  for,  302 

plates  for  drying  gun-cotton,  186 
recovery  of,  240,  241 
Corals,  imitations  of,  295 


Cotton,  3-6 

apparatus  for  dissolving,  231,  232 
chemical  composition  of,  6 
destruction  of  structure  of,  171 
determination  of  value  of,  5 
dissolving  the,  in  cuprammonium, 

231-233 

fabrics,  transparent  plates  of  vis- 
cose from,  136,  137 
fibre,  behavior  of,  towards  caustic 

alkalies,  14 
diameter  of,  5 
length  of,  5 
microscopical  appearance  of, 

4,  5 

filtering  solution  of,  233 
hollander  for  dissolving,  231 ,  232 
judging  progress  of  solution  of,  232 
nitrated,    phvsical    behavior    of, 

212,  213 
results    of    examination    of, 

212,  213 
washing  of,  213 
nitration  of,  178-183,  210,  213 
plant,  18 

fruit  of,  4 
preparation     of    chemically-pure 

cellulose  from,  6 

purification  of,  174,  175,  230,  231 
solution,  spinning  the,  234-236 
Cross,  preparation  of  viscose  according 

to,  134,  135 

Crushing  process,  preparation  of  me- 
chanical wood-pulp  by  the,  45-47 
Cuffs  and  collars  from  celluloid,  297, 

298 
Cuprammonium,  229 

apparatus   for   converting  cupric 

hydroxide  into,  238,  239 
dissolving  cotton  in,  231-233 
preparation  of,  237-240 
Cupric  sulphate,  237 

solution,  filtering  of,  237 
Cuprous  salts  for  denitration,  226 
Cylinder  sieves,  36,  37 

TkEHYDRATION  of  pulp,  40,  41 
-L/     Denitrating    fluid,    additions   to 

the,  225 
composition      of, 

220,  221 
Denitration  of  artificial  silk,  220,  221, 

225-228 
Dentists,  celluloid  for  the  use  of,  298, 

299 

Dextrin  from  cellulose,  12 
Dextrose,  maximum  yield  of,  1C4,  105 
temperature  for  the  formation  of, 
105 


INDEX. 


337 


Dinitro-cellulose,  195 

Disintegrators,  122 

Distillation,  101 

Disulphur  dichloride,  preparation  of, 

328-331 

quantities  of,  re- 
quired for  the 
conversion  of  oils 
into  factis,  326 

Doll  heads  of  viscoid,  159 

Door  handles,  159 

Dressing,  use  of  viscose  as  a,  143-145 

Drying  apparatus  for  pulp,  41,  42 
chamber  for  celluloid,  279,  280 
room,  heating  the,  186,  187 

Du  Vivier,  207 

Du  Viviens  artificial  silk,  222-224 

Dye-baths  for  artificial  silk,  255 

EBONITE,  310 
Eder's  investigations,  170 
Elastic    masses    from    nitro-cellulose, 

197-200 

rubber  masses,  311,  312 
Electric  current,  preparation  of  cellu- 
lose with  the  assistance  of  the, 
73-75 
process,  51 
Encrusting  substance,  3 

solution   and   destruc- 
tion of,  20 

Esparto,  use  of,  77,  78 
Esters,  cellulose,  200-204 

formation  of,  from  cellulose,  14 
Ether,  apparatus  for  the  recovery  of, 

275-278 

boiling  point  of,  274 
recovery  of,  274-278 
Explosive  gun-cotton,  187,  188 

FABRICS     for     the     imitation    of 
leather,  146 

viscose  for  marking,  143 
Factis  masses,  322,  323 

preparation  of,  on  a  large  scale, 

326-328 

quantities  of  disulphur  dichloride 
required  for  the  conversion  of 
oils  into,  326 
white,  325-328 
Felt,  impregnation   of,  with   viscose, 

151,  152 
nature  of,  151 

Fermentation,  yeast  for,  100,  101 
Fibre,  vulcanized,  90-92 
Fibres,  plants  producing.  6 
Fibroin,  205,  206,  224 
Filling  materials,  celluloid  with,  289- 
293 

22 


Films,  preparation  of,  153 
Filter  for  collodion  solution,  214 
for  cotton  solution,  233 

viscose  solution,  248,  249 
-presses,  41 
Filtering  material,  233 

water,  34 

Fir,  yield  of  cellulose  from,  59 
Flax,  6,  18 
Flock  paper,  141 
Flowers,   artificial,    celluloid    lacquer 

for,  305 

artificial,   viscose    in   the   manu- 
facture of,  152,  153 
Frames    for    drying  gun-cotton,   186, 

187 
Frank's  process  for  the  neutralization 

of  lye,  80 

Freitag's  grinding  machine,  31,  32 
Fremery,  M.,  and  Urban,  J.,  artificial 
silk  according  to,  242-244 

GELATINE  silk,  206,  253,  254 
Glacial  acetic  acid,  use  of,  for 

dissolving  nitro-cellulose,  223 
Glue  silk.  206 
Goldsmith,  J.  R. ,  camphor-substitute 

proposed  by,  307,  308 
Gold  sulphur,  309 
Gray  on  celluloid,  286 
Grinding  machines  for  wood,  27-34 

wood,  water  used  for,  34 
Grindstone  for  grinding  wood,  27 
Gums,  impression  of,  299 
Gun-cotton,  161-204 

boiling  or  steaming  of,  184 
changes  in,  184 
comminution  of,  184 
compression  of,  187,  188 
drying  the,  186,  187 
explosive,  187,  188 

acid  mixture  for,  177 
for  blasting  purposes,  187 
ignition  of,  183 
modern  views  regarding  the 

composition  of,  162 
perfectly  dry,  storing  of,  187 
preparation  of.  174,  175 
soluble,  acid  mixture  for,  177 
or  collodion-cotton,  190- 

192 

solvents  for,  191,  192 
storing  of,  185,  186 
testing  of,  185 
washing  the,  183-186 
Gutta-percha  printing  blocks,  289 
Guttmann's  plan  of  drying  gun-cotton, 
186 


338 


INDEX. 


HAIK  or  wool,  vegetable,  3 
Hemlock  spruce,  yield  of  cellu- 
lose from,  59 
Hemp,  6,  18 

Henckel-Donnersmark'  s     process     of 
preparing  cellulose  acetic-ester,  200, 
201 
Henriques,  H. ,  investigations  of,  325, 

326 
Hollander,  122 

for  dissolving  cotton,  231,  232 
preparation   of  viscose  solu- 
tion, 248 
reduction    of  gun-cotton   in  the, 

184,  185 
Honig's  process  for  the  utilization  of 

lye,  81 

Horse-hair,  artificial,  244,  245 
Houses,  portable,  pasteboard  for,  151 
Hummers  process  of  making  artificial 

silk,  207,  208 
Humus  substances,  115 
Hyatt,  invention  of  celluloid  by,  263 
preparation  of  celluloid  according 

to,  266-268 

Hydraulic  press,  protection  of  the,  213 
Hydrocarbons,  heavy,  use  of,  in  the 

production  of  oxalic  acid,  112 
Hydro-cellulose,  9-11 

composition  of,  9 
manufacture  of,  on  a  large 

scale,  9-11 

preparation  of  an  acetyl  de- 
rivative from,  202/203 
properties  of,  10 
sulphuretted,  as  rubber  sub- 
stitute, 328,  329 
Hydrochloric    acid,  action   of,   upon 

cellulose,  13 
boiling  wood   with, 

98,  99 
disintegration         of 

wood  by,  51,  52 

Hydrochlorides,  disintegration  of  wood 
by,  106 

TNCRUSTATIONS,  300 

JL     Indigo-blue  on  celluloid,  286 

Iron  in  cellulose,  73 

recovery  of  copper  by  means  of, 
240,  241 

vessels,  celluloid  lacquer  for,  306 
Ivory,  imitation  of,  291 ,  292 

JAWS,  impression  of  human,  299 
Jute,  6 

bagging,  use  of,  78 


KEEGAN'S  process,  56,  57 
Keller,  F.  G.,  22 

Kellner's  process  of  preparing  cellu- 
lose   with    the    assistance    of     the 
electric  current,  73-75 
Kneading  and  mixing  paddle,  158 

machine.  157,  138 

Knots,  machine  for  removal  of,  25,  26 
Kristaline,  303 

LACQUEE,  celluloid,  302-306 
durable  and  resisting,  314 
Lactic  acid,  126 
Langhaus's  process  for  the  preparation 

of  artificial  silk,  208,  209 
Lapis  lazuli,  imitation  of,  301 
Lead  acetate,  treatment  of  nitro-cellu- 

lose  with,  189 

Leather,  artificial,  coloring  of,  147 
fabrics  for,  146 
main   point   in  the  pre- 
paration of,  145 
preparation  of,  145—152 
viscose  solutions  for,  146, 

147 

hangings,  imitations  of,  141,  142 
nature  of,  145 

Lederer,  L. ,  preparation  of  an  acetyl 
derivative  of  cellulose  according  to, 
202,  203 

Lehner's  artificial  silk,  224,  225 
Liber,  3 

Liebrecht's  grinding  machine,  33,  34 
Lignin,  solution  and  destruction  of,  20 
Limestone,  solid  tufaceous,  62 
Linseed  oil,  316 

final  oxidation  of,  318 
heating  of,  317 
oxidation  of,  316 
testing  of.  317 
Long-staple  cotton,  5 
Luck,  A.,  and  Gross,  C.  F. ,  process 
for  increasing  the  stability  of  nitro- 
cellulose of,  189 

Lunge,  G.,  and  Bebie,  J.,  investiga- 
tions of,  167 

Weintraub,   E.,  investi- 
gations of,  163 
Lustra-cellulose  and  cellulose  artificial 

silk,  229-245 
threads  from,  246-262 
Lye  and  wood,  proportion  between,  68 
apparatus  for  the  preparation  of, 

61-66 

boiling  the  wood  with,  67-70 
neutralization  of,  80,  81 
organic  substance  in,  80 
pollution  of  streams  by,  80 
preparation  of,  61-66 


INDEX. 


339 


Lye,  reservoirs  for,  65,  60 

utilization  of,  in  tanning,  80,  81 
Lyes,  exhausted,   utilization   of,    and 
their  neutralization.  78-81 

mixed,  preparation  of,  113 

MAGNESIUM  viscose,  133 
use  of,  for  sizing 

paper,  139,  140 

Magnus,  preparation  of  celluloid  ac- 
cording to,  270,  271 
Manila  hemp,  6 

Maps,  celluloid  lacquer  for,  302 
Marble,  imitation  of,  290 

variegated,  imitation  of,  301 
Marine  glue,  313,  314 
Mechanical   wood-pulp,  definition  of, 

22 
or  wood-stuff,  22- 

49 

preparation  of,  by 
tne      crushing 
process,  45-47 
Melting  apparatus  for  oxalic  acid;  113, 

114 
Metallic    salts,    behavior    of    viscose 

towards,  133,  134 
treatment  of  nitro-cellu- 

lose  with,  189 

Mercer,  John,  discovery  of,  14 
Mercerization,  14 
Metals,  celluloid  lacquer  for,  303,  305, 

306 

for  incrustations,  300 
Methyl  alcohol,  use  of,  for  dissolving 

nitro-cellulose,  224 
Milk-white,  definition  of,  290 
Millar,  A.,  207 

Millar's  artificial  silk,  253,  254 
Mitscherlich's  process,  59-73 
Mixing  machine,  157,  158 
Montejus,  231 
Mosaics,  celluloid,  301,  302 
Mother-lye,  115 
Mould,  plaster  of  Paris,  296 
Moulding  hollow  articles  of  viscoid, 

159 
Moulds  for  viscoid,  159 

NAPHTHALINE,    substitution  of, 
for  camphor,  306,  307 
Nettle,  6 

New  Zealand  flax,  6 
Nitrated  cotton,  physical  behavior  of, 

212,  213 
results  of  examination  of, 

212,  213 
washing  of,  213 
Nitrating  apparatus,  179,  180 


Nitrating  fluid,  164,  210,  211 

condition  of  the,  177,  178 
nature  of,  176,  177 
fluids,  composition  of,  172.  173 

regeneration  of,  177 
vessels,  177,  211 
Nitration,  acid  for,  175-177 

centrifugal  apparatus  for,  181,  182 

degrees  of,  167 

effect  of  higher  temperatures  upon, 

170 

execution  of,  178-183 
for  the  production  of  collodion- 
cotton,  191 

highest  degrees  of,  165 
influence  of  the  content  of  water 

in  the  acid  mixture  upon,  168 
of  cotton,  210-213 
process  of,  164,  165 
stone- ware  vessels  for,  176 
time  required  for,  181 
with  dry  saltpetre  and  sulphuric 

acid,  223 
Nitric  acid,  action  of,  upon  cellulose, 

13 

combinations  formed  by  the 
action  of,  upon  cellulose, 
161 

for  collodion-cotton,  190 
the  manufacture   of  very 
explosive  products,  175 
oxidation  of  linseed  oil  with, 

318 

storage  of,  176 
use  of,  for  the  disintegration 

of  the  wood-fibre,  51 
and  sulphuric  acids,  mixtures  of, 
for  the  preparation    of   nitro- 
cellulose, 163 
Nitro-cellulose,  161-204 

action  of,  towards  polarized 

light,  165,  166 
and  cellulose  silks,  difference 

between,  261 

calculation  of  nitrogen  con- 
tained in,  166,  167 
changes  in,  188.  189 
content  of  nitrogen  in,  164 
elastic  masses  from,  197-200 
formation  of,  162,  163 
increasing    the    stability   of, 

188-190 

masses,  inflammability  of,  199 
powders  for  mixing  with, 

199 

mixtures    of    sulphuric    and 
nitric  acids  for  the  prepa- 
ration of,  163 
preparation  of,  163 


340 


INDEX. 


Nitrocellulose,  reaction  of,  192 

solution   of,   in  volatile  sol- 
vents, 197 

solvents  for,  197,  223,  304 
spontaneous  ignition  of,  227, 

228 

-celluloses,  16,  17 
analyses  of,  174 
composition  of,  194 
solubility  of,  169,  170 
compounds,  formation  and  com- 
position of,  161,162 
-oxycelluloses,  173 
Nitrogen,  calculation  of,  contained  in 

nitro-cellulose,  166,  167 
Nuts  from  viscoid,  160 

OBJECTS  of  art  from  celluloid,  300 
Observatories,    paste-board     for, 

151 

Octo-nitro-cellulose,  169 
Oil,  oxidation  of,  320,  321 
-rubber,  316-322 

additions  to,  324 
manufacture  of,    on  a  large 
scale  by  means  of  thick  oil, 
319-322     , 

old,  restoration  of,  319 
uses  of,  319 
thick,  manufacture  of  oil-rubber 

by  means  of,  319-322 
working  of,  321,  322 
vulcanized,  324,  325 
Oils,  drying,  316 
non-drying,  316 

quantities  of  disulphur  dichloride 
required  for  the  conversion  of, 
into  factis,  326 
sulphured,  323,  324 
Oser's  grinding  machine,  30 
Oxalic    acid     from    wood     cellulose, 

preparation  of,  108-118 
formation  of.  109 
melting  apparatus  for,  113, 

114 

occurrence  of,  108 
preparation   of,    on    a    large 

scale,  113 

proportion    between    caustic 
soda  and  caustic  potash  in 
the  production  of,  111 
pure,  from   sodium   oxalate, 

116 

production  of,  117,  118 
use  of  heavy  hydrocarbons  in 

the  production  of,  112 
working  up  the  melt,  115-117 
yields  of,  from  sawdust,  110, 
111 


Oxygen,  oxidizing  action  of,  316 

PANS,  evaporating,  117 
Paper,   cellulose  in    the    manu- 
facture of,  16 
changes  in,  by  parchmentiz- 

ing,  87,  88 

mills,  viscose  for  use  in,  133 
nature  of,  18,  50 
sizingof,  with  viscose, 139, 140 
suitable  for  parchmentizing, 

83,84 
to  be  parchmentized,  nature 

of,  83,  84 

use  of  viscose  in  the  manu- 
facture of,  139-141 

Parchment  of  special  thickness,  pre- 
paration of,  83,  84,  88 
paper,  behavior  of,  towards   ad- 
hesive agents,  89,  90 
coloring  of,  89 
flexible,  88-90 
manufacture   of,   on   a   large 

scale,  85-87 
properties  of,  87,  88 
removal  of  acid  from,  86 
vegetable,  16,  82,  92 

uses  of,  90 

Parchmentizing  apparatus,  85-87 
changes  in  paper  by,  87,  88 
effect  of  sulphuric  acid,  82,  83 
sulphuric  acid  used  for,  84,  85 
temperature  for,  84 
Pasteboard,  fire-proof,  for  roofing,  16 
fire-proofing  of,  151 
for  portable  houses,  151 
impregnation  of,  with  viscose,  150, 

151 
Pauly,  Dr.  Hermann,  208,  230 

artificial  silk  of,  230- 

236 
Peit,  A.,  process  for  the  manufacture 

of  artificial  silk,  patented  by,  227 
Photography,  viscose  in,  153,  154 
Pictures,  transferring  of,  to  celluloid 

articles,  287-289 
Pine,  steaming  of.  44 

yield  of  cellulose  from,  59 
Plants,  structure  of.  1 
Plastite  masses.  310,  311 
Polariscope,  results  of  examination  of 

nitrated  cotton  with  the,  212,  213 
Polarized  light,  action  of  nitro-cellu- 
lose towards.  165.  166 
Poplar,  yield  of  cellulose  from,  59 
Potash,  caustic,  behavior  of  cellulose 

towards,  14 

Potassium   carbonate,    conversion    of, 
into  caustic  potash,  115 


INDEX. 


341 


Potassium  carbonate,  recovery  of,  115 
Printing  blocks,  gutta-percha,  289 

on  celluloid,  287-289 
Pulp,  185 

bleaching  agents  for,  43 

change  in  color,  of,  42 

color  of,  42 

dehydration  of,  40,  41 

drying  apparatus  for,  41,  42 

effect  of  water  on,  34 

from  steamed  wood,  43 

bleaching  of,  48 

preparation   of,  by  the  crushing 
process,  45-47 

properties  of,  42,  43 

separation  of,  from  water,  39 

straw,  bleaching  of,  77 

thoroughly  dried,  preparation  of, 

40,  41 
Pyroxylin,  161-204 

RAPE  oil,  324 
Rasch-Kirchner's    machine    for 
the  preparation  of  pulp  by  the 
crushing  process,  45-47 
Reagents,  chemical,  behavior  of  nat- 
ural   and    artificial   silks    towards, 
259-262 

Red  on  celluloid,  285,  286 
Refiner,  37,  38 

Resins,  addition  of,  to  rubber,  309 
Rib-heaters,  252 

Richter's  investigations  regarding  the 
denitration  of  artificial  silk,  225, 226 
Roofing  boards,  47,  48 

fire-proof  paste-board  for,  16 
Rubber,  additions  to,  399 
artificial,  197-200 
compounds,  309-314 
filling  substances  for,  309 
increasing  demand  for,  315 
-leather,  312,  313 
masses,  elastic,  311,  312 
substitute,    sulphuretted     hydro- 
cellulose  as,  328,  329 
substitutes,  315-331 
actual,  316 
groups  of,  315 
Ruby  shellac,  309 

SAUSAGE  casings,  90 
Sawdust,  action  of  a  mixture  of 
caustic  soda    and    caustic 
potash  upon,  109,  110 
fermentable  sugar  from,  94, 

95 
yields  of  oxalic   acid   from, 

110,  111 
Scarlet  on  celluloid,  285,  286 


Schulz's  process  for  rendering  nitro- 
cellulose stable,  189,  190 
Screws  from  viscoid,  160 
Seidel,  preparation  of  viscose  accord- 
ing to,  135-138 
Sericin,  205,  206 
Shaking  sieves,  Voith's,  35,  36 
Shellac,  309 
Short-staple  cotton,  5 
Shuttles  from  viscoid,  160 
Sieves,  cylinder,  36,  37 

Voith's  shaking,  35,  36 
Silk,  artificial,  17,  205-228 

according  to  M.  Fremery  and 

J.  Urban,  242-244 
apparatus  for  spinning,  217- 

219 
behavior  of,   in   a   chemical 

respect,  259-262 
bleaching  of,  221 
Bronnert's,  236,  237 
cellulose,  229-245 
Chardonnet,  209-222 
denitration  of,  220,  221,  225- 

228 

dye  baths  for,  255 
Lehner's.  224,  225 
Millar's,  253,  254 
optical  examination  of,  256 
Pauly's.  230-236 
Peit's,  227 
tenacity  of,  256,  257 
varieties  of,  206-209 
colored  artificial,  preparationrof, 

221,  222 

industry,  artificial,  historical  de- 
velopment of,  207-209 
microscopical  appearance  of,  206 
raw,  color  of,  205 

composition  of,  205 
scouring  or  boiling  of,  205, 

206 

sources  of.  205 
table  showing  diameters  of  various 

kinds,  256 
Silks,    cellulose    and    nitro-cellulose, 

difference  between,  261 
natural  and  artificial,  behavior  of, 
towards  chemi- 
cal    reagents, 
259-262 
difference  between, 

255 

Silver  gray  on  celluloid,  286 
Sinclair^ s  boiler,  54,  55 
Size,  use  of  viscose  as  a,  143-145 
Sizing,  use  of  viscose  for,  16 
Soda,  caustic,  and  cellulose,  quantita- 
tive proportions  of,  122 


342 


INDEX. 


Soda,    caustic,   behavior  of    cellulose 

towards,  14 
disintegration  of  wood  by,  56, 

57 
-cellulose,  121 

commencement  of  formation 

of,  122,  123 
constancy  of,  125 
heating  of,  by  storing,  124 
injurious  changes  in,  125 
preparation  of,  123,  124 
products  formed   by  the  de- 
composition of,  126 
storing  of,  124-126 
temperature  for  storing,  125, 

126 

vessels  for  storing,  125 
lye  and  carbon  disulphide,   pro- 
portion between,  127 
boiling  wood  with,  53 
disintegration  of  the  encrust- 
ing substance  by,  52,  53 
preparation  of  cellulose,  by  means 

of,  52-59 
process,  51 

wood  suitable  for  the,  52 
recovery  of,  53,  79 
viscose,  addition  of  bodies  to,  133 
Sodium  oxalate,  115 

pure  oxalic  acid  from,  116 
sulphite,  preparation  of  cellulose 

by  means  of,  58,  59 
use    of,   as  a  substitute    for 

caustic  soda,  53 
Soles,  fabrics  for,  150 
Solid  spirit,  203,  204 
Soluble  gun-cotton,  or  collodion-cotton, 

190-192 
Sorters,  35 

Sorting  ground  wood,  35-40 
Spinners,  construction  of,  234 
manufacture  of,  216,  217 
Spinning  apparatus,  217-219 

for  viscose  solution,  249, 

250 

cotton  solution,  234-236 
room,  removal  of  vapors  from  the, 

216,  217 

Spirit,  solid,  203,  204 
Splitting  machine,  26 
Spools  from  viscoid,  160 
Stains,  process  for  the  preparation  of 
celluloid  employed  by  the  factory 
at,  265 

Stamping  mill,  71 
Starch,  oxalic  acid  from,  108 
Steamed  wood,  microscopical  exami- 
nation of,  45 
pulp  from,  43-45 


Steaming  wood,  apparatus  for,  44 
Stearn,  preparation  of  textile  threads 

according  to,  252,  253 
Steel  engravings,  celluloid  lacquer  for, 

302 
Steenstrup' s     method     of     preparing 

rubber  substitutes,  315.  316 
Sthamer,  preparation  of  sulphuretted 

hydro-cellulose  according  to,  328 
Sthamer' s  process   of    manufacturing 

hydro-cellulose,  10,  11 
Stone- ware  vessels  for  nitration,  176 
Straw,  boiling  of,  with  lye,  76.  77 
cellulose  from,  18,  19,  75-78 
preparation  of,  75,  76 

of  cellulose  from,  2,  3 
pulp,  bleaching  of,  77 
winnowed,  working  of,  76 
yield  of  cellulose  from,  77 
Sugar    and    alcohol,    production    of, 

from  wood-cellulose,  93-107 
fermentable,  conversion  of  cellu- 
lose into,  17 

from  wood,  more  modern 
methods  for  the 
production  of, 
98-102 

older  methods  for 
the  production 
of,  94-98 

Sulphite-cellulose   according    to  Mit- 
scherlich's  process,  59- 
73 
plant,  water  required  in 

a,  59,  60 
preparation  of  wood  for, 

60 

viscose  from.  135,  136 
process,  51 

irregularities  in,  66 
operations  in  the,  61 
preparation  of  lye  for,  61-66 
of  sulphurous  acid  for,  62 
solution,  preparation  of,  61-66 
Sulphites,    preparation     of    cellulose 

with  the  assistance  of,  59-73 
Sulphur  burning.  62 

causes  of  incomplete  combustion 

of,  62 

unburnt,  test  for,  62,  63 
Sulphured  oils,  323,  324 
Sulphuretted  hydro-cellulose  as  rubber 

substitute,  328,  329 
hydrogen,  evolution  of,  from  vis- 
cose solution.  130,  131 
Sulphuric  acid,  behavior  of  celluloid 

towards,  282 
concentrated,   effect    of, 
on  thread,  243,  244 


INDEX. 


343 


Sulphuric  acid,  effect  of,  upon  cellulose, 

12,  13,  82 
upon  wood,  103 
for  collodion-cotton,  190 

nitration,  176 
parchmentizing  effect  of, 

82,  83 

production  of,  105 
recovery  of,  86,  87 
storage  of,  176 
used  for  parchmentizing, 

84,  85 

and  nitric  acids,  mixtures  of,  for 
the  preparation  of  nitro-cellu- 
lose,  163 
anhydride,  treatment  of  wood  by, 

106 

Sulphurous  acid,  action  of,  upon  cel- 
lulose, 13 

bleaching  pulp  with,  43 
preparation  of,  62 
recovery  of,  70 

TABLE  showing  changes   in   paper 
by  parchmentizing,  88 
comparative   tenacity  of 

artificial  silk,  257 
diameters      of      various 

kinds  of  silk,  256 
effect  of  higher  tempera- 
tures  upon    nitration, 
170 

influence  of  content  of 
water  in  the  acid  mixt- 
ure upon  nitration, 
168 

proportion  between 
caustic  soda  and  caustic 
potash  in  the  produc- 
tion of  oxalic  acid, 
110,  111 

quantities  of    disulphur 
dichloride       required 
for  the   conversion  of 
oils    into  factis.  326 
Tanning,  utilization  of  lye  in,  80.  81 
Tar  colors,  printing  with,  on  celluloid, 

289  < 

Tartaric  acid,  action   of,  upon  cellu- 
lose, 13 
Textile  threads,  collodion-cotton  for, 

190 

from  pure  cellulose,  208,209 
viscose.  246-262 

according    to    Stearn, 

252,  253 

produced  by  artificial 
means,  general  proper- 
ties of,  254-262 


i  Thorn's  investigations   regarding  the 

production  of  oxalic  acid,  109-112 
Thread,  drying  process  for,  242,  243 
effect   of   concentrated   sulphuric 

acid  on,  243,  244 
Threads,  cellulose,  229-245 
collector  for,  234 
effect  of  water  on,  254 
from  lustra-cellulose.  246-262 
microscopical     examination      of, 

255,  256 

reeling  up  of,  235 
textile,  from  viscose,  246-262 

produced  by  artificial  means, 
general  properties  of,  254- 

uniform,  of  larger  diameter,  245 
Tissue,  loosely   woven,  treatment  of, 

137 

mode  of  sizing  a,  with  viscose,  144 
Torpedoes,  gun-cotton  for  loading,  188 
Tortoise-shell,  imitation  of,  292 
Tower,  absorbing,  for  the  preparation 

of  lye.  63-66 
Tribouilletand  Besancele,  preparation 

of  celluloid  according  to,  268,  269 
Tubes,  celluloid,  294 


I 


NGERER'S  boiling  process,  55 


VARNISH,  resisting,  preparation  of, 
325 

Vegetable  parchment,  16,  82-92 
Velvet  hangings,  imitations  of,  141, 142 
Ventilating  hood,  178,  179 
Victoria  lacquer,  303 
Violet  on  celluloid,  286 
Viscoid  and  viscose,  119-160 

articles,  painting  of,  159,  160 
conversion  of  viscose  into,  132, 133 
masses,  154-160 

preparation  of  larger  quanti- 
ties of,  157-160 
properties  of,  157 
white,  155,  156 

moulding  hollow  articles  of,  159 
plates  and  blocks  from,  132,  133 
cause  of  dull  specks  in,  133 
uses  of,  160 
Viscose  and  viscoid,  119-160 

apparatus  for  preparing,  127 
as  a  size  or  dressing,  143-145 
behavior  of.  towards  metallic 

salts,  133,  134 
cellulose  for  the   preparation  of, 

121,  122 

chemically  pure,  preparation  of, 
138 


344 


INDEX. 


Viscose,  coloring  of,  247 

conversion  of,  into  viscoid,  119, 

]20,  132,  133,  250 
cost  of  producing  threads  from, 

246 

experiments  with,  246 
films  of,  133 
for  marking  fabrics,  143 
impregnation   of   felt   with,  151, 

152 
paste  board  with, 

150,  151 

in  cloth  printing,  142,  143 
photography,  153,  154 
the    manufacture    of    artificial 

flowers,  152,  153 
of  wall  paper.  141, 142 
incorporation   of    foreign    bodies 

with,  155,  156 
modifications  in    the    process  of 

preparing,  120 
preparation  of,  126-128 

according  to  Cross, 

134,  135 
to  Seidel,  135- 

138 

films  from,  153,  154 

leather-like     bodies 

by  means  of,  145- 

152 

on    a    large     scale, 

121-124 
small  scale,  120, 

121 

pure  cellulose  from,  246 
replacing    the    soda   in,    by   am- 
monia, 131 
shipping  of,  130 
solution,  changes  in,  130 

decomposition  of,  130,  131 
filtering  of,  248,  249 
for  the  preparation  of  silk- 
threads,  209 

preparation  of,  128,  129,  248 
spinning  apparatus  for,  249, 

250 
solutions  for  the  preparation  of 

artificial  leather,  146, 147 
properties  of,  130-132 
stability  of,  129 
storing  of,  129,  130 
temperature  for  storing,  129,  130 
textile  threads  from,  246-262 

according       t  o 
Stearn,    252, 
253 
*  threads,  132 

quality  of,  247 
treatment  of,  250,  251 


Viscose,  use  of,  in  the  manufacture  of 

paper,  139-141 
uses  of,  16,  138.  139 
vessels  for  shipping,  130 

storing,  129 
Voelter,  Heinrich,  22 

grinding     machine     of, 

28-30 
process  of  wood  grinding 

of,  23 
Voith's  shaking  sieves,  35,  36 

wood-grinding  machine,  31 
Vulcanized  cellulose,  90-92 
fibre,  90-92 
oil,  324,  325 

WALL  paper,  viscose  in  the  manu- 
facture of.  141,  142 
Wash  room,  183 

tank,  183 

Washing  machines,  57 
Waste  water,  discharge  of,  59,  60 
Water,  behavior  of  celluloid  towards, 

8,  9,  282 

effect  of,  on  pulp,  34 
filtering  of,  34 
separation  of  pulp  from,  39 
used  for  grinding.  34 
Weapons,  celluloid  lacquer  for,  303 
White  factis,  325-328 
Winkler,  Cl.,  experiments  of,  42 
Wood,  alcohol  from,  12 

Classen's      process, 

102-107 
value  of,  102 
and  chemicals,  consumption  of,  59 

lye,  proportion  between,  68 
apparatus  for  steaming,  44 

the    production   of 

alcohol  from,  97 
battery  for  lixiviation  of,  57 
boiling  of,  under  pressure,  98,  99 
with  lye,  67-70 
soda  lye,  53 
cellulose  from,  3 

preparation  of,  50-81 

of   oxalic   acid    from, 

108-118 

production  of  sugar  and  alco- 
hol from,  93-107 
dead-ground,  33 

disintegration  of,  by  chlorine,  106 
hydrochloric 
acid,  51 ,52 
hypo  chlor- 
ides, 106 

encrusting  substance  of,  3 
extractive  substances  in,  108 
-fibre,  disintegration  of,  byacids,51 


INDEX. 


345 


Wood  for  grinding,  23,  24 
grinding  machines,  27-34 

process,  first  patent  for,  22 

Voelter's,  23 

grindstone  for  grinding,  27 
ground,    physical    properties    of, 

48,49 

sorting  of,  35-40 
hydraulic   pressure   in    grinding, 

33,34 
machine  for  removing  knots  from, 

25,  26 
for  removing  the  bark  from, 

24,  25 
mill  for  the  further  reduction  of, 

37,38 

more  modern  methods  for  the  pro- 
duction of  fermentable  sugar 
from,  94-98 

nature  of,  to  be  worked  for  alco- 
hol, 96-98 

older  methods  for  the  production 
of  fermentable  sugar  from,  94- 
98 

origin  of  the  idea  of  grinding,  22 
preparation  of  cellulose  from,  50- 

81 
of,  for  sulphite  cellulose, 

60 
-pulp,   chemical,  preparation   of, 

50-81 

mechanical,  definition  of,  22 
or  wood-stuff;  22-49 
preparation  of,  by  the 
crushing  process,  45- 
47 

properties  of,  42,  43 
qualities  of,  19 
reduction  of,  19,  94 
soaking  of,  94 

spirit,  use  of,  for  dissolving  nitro- 
cellulose, 224 


Wood,  splitting  machine  for,  26 

steamed,  microscopical   examina- 
tion of,  45 
pulp  from,  43-45 
-stuff,  definition  of,  22 

or     mechanical     wood-pulp, 

22-49 

suitable  for  the  soda  process,  52 
tar,  15 

threads  from,  21 
to  be  ground,  preparation  of,  24- 

26 

treatment  of,  by  sulphuric  anhy- 
dride, 106 
varieties  of,  suitable  for  grinding, 

23,24 
for  the  production 

of  alcohol,  97 
for   sulphite-cellulose, 

60,  61 

-vessels,     change     of     cellulose- 
vessels  into,  1 
vinegar,  15 

water  used  for  grinding,  34 
yield  of  alcohol  from,  107 
Wool  tree,  6 

Wrapping  paper,  sizing  of,  with  vis- 
cose, 140 
stout,  44 

T7EAST  for  fermentation,  100,  101 


ZAPON,  303 
Zetterlund,    process    of,   for    the 
production  of  fermentable  sugar 
from  wood.  94,  95 
Zinc  acetate,  treatment  of  nitro-cellu- 

lose  with,  189 

Zuhl   and  Eisemann,  camphor-substi- 
tutes proposed  by,  307 


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ARROWSMITH.— The  Paper-Hanger's  Companion: 

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Directions  for  Making  Handkerchief  Perfumes,  Smelling-Salts, 
Sachets,  Fumigating  Pastils ;  Preparations  for  the  Care  of  the  Skin, 
the  Mouth,  the  Hair;  Cosmetics,  Hair  Dyes,  and  other  Toilet 
Articles.  By  G.  W.  ASKINSON.  Translated  from  the  German  by  IsiDOR 
FURST.  Revised  by  CHARLES  RICE.  32  Illustrations.  8vo.  $3.00 

8RONGNIART.— Coloring  and  Decoration  of  Ceramic  Ware. 
8vo.  •*  •»,        .     -  .        .        .        -.  -    *. -v     t    -".- *    •  '      $2.50 

BAIRD. — The  American  Cotton  Spinner,  and  Manager's  and 
Carder's  Guide: 

A  Practical  Treatise  on  Cotton  Spinning ;  giving  the  Dimensions  and 
Speed  of  Machinery,  Draught  and  Twist  Calculations,  etc. ;  with 
notices  of  recent  Improvements :  together  with  Rules  and  Examples 
lor  making  changes  in  the  sizes  and  numbers  of  Roving  and  Yarn. 
Compiled  from  the  papen  of  the  late  Ro»£*T  H.  BAIRD.  lanio. 

1 1. 5° 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


BAKER. — Long-Span  Railway  Bridges  : 

Comprising  Investigations  of  the  Comparative  Theoretical  and 
Practical  Advantages  of  the  various  Adopted  or  Proposed  Type 
Systems  of  Construction  ;  with  numerous  Formuke  and  Tables.  By 
B.  BAKER.  i2mo $1.00 

BRAN  NT. — A    Practical    Treatise  on    Distillation  and  Rec- 
tification of  Alcohol : 

Comprising  Raw  Materials  ;  Production  of  Malt,  Preparation  of 
Mashes  and  of  Yeast ;  Fermentation  ;  Distillation  and  Rectification 
and  Purification  of  Alcohol  ;  Preparation  of  Alcoholic  Liquors, 
Liqueurs,  Cordials,  Bitters,  Fruit  Essences,  Vinegar,  etc. ;  Examina- 
tion of  Materials  for  the  Preparation  of  Malt  as  well  as  of  the  Malt 
itself;  Examination  of  Mashes  before  and  after  Fermentation  ;  Alco- 
holometry,  with  Numerous  Comprehensive  Tables  ;  and  an  Appendix 
on  the  Manufacture  of  Compressed  Yeast  and  the  Examination  of 
Alcohol  and  Alcoholic  Liquors  for  Fusel  Oil  and  other  Impurities. 
By  WILLIAM  T.  BRANNT,  Editor  of  "  The  Techno-Chemical  Receipt 
Book."  Second  Edition.  Entirely  Rewritten.  Illustrated  by  105 
engravings.  460  pages,  8vo.  (Dec.,  1903)  .  .  .  $4.00 

BAKR.— A  Practical  Treatise  on  the  Combustion  of  Coal  : 
Including  descriptions  of  various   mechanical  devices  for  the  Eco- 
nomic Generation  of  Heat  by  the  Combustion  of  Fuel,  whether  solid, 
liquid  or  gaseous     8vo.    .         .          .  .          .         .         $2.50 

B  ARR.— A  Practical  Treatise  on  High  Pressure  Steam  Boilers: 
Including  Results  of  Recent  Experimental  Tests  of  Boiler  Materials, 
together  with  a  description  of  Approved  Safety  Apparatus,  Steam 
Pumps,  Injectors  and  Economizers  in  actual  use.  By  WM.  M.  BARR. 
204  Illustrations.  8vo #3- oo 

BAUERMAN.— A  Treatise  on  the  Metallurgy  of  Iron  : 

Containing  Outlines  of  the  History  of  Iron  Manufacture,  Methods  of 
Assay,  and  Analysis  of  Iron  Ores,  Processes  of  Manufacture  of  Iron 
and  Steel,  etc.,  etc.  By  H.  BAUERMAN,  F.  G.  S.,  Associate  of  the 
Royal  School  of  Mines.  Fifth  Edition,  Revised  and  Enlarged. 
Illustrated  with  numerous  Wood  Engravings  from  Drawings  by  J.  B. 
JORDAN,  izmo,  ........  $2.00 

BRANNT.  -The  Metallic  Alloys  :  A  Practical  Guide 

For  the  Manufacture  of  all  kinds  of  Alloys,  Amalgams,  and  Solders, 
used  by  Metal-Workers  :  together  with  their  Chemical  and  Physical 
Properties  and  their  Application  in  the  Arts  and  the  Industries  ;  with 
an  Appendix  on  the  Coloring  of  Alloys  and  the  Recovery  of  Waste 
Metals.  By  WILLIAM  T.  BRANNT.  34  Engravings.  A  New,  Re- 
vised, and  Enlarged  Edition.  554  pages.  8vo.  .  .  $4.50 

BEANS. — A  Treatise  on  Railway  Curves  and   Location  of 

Railroads : 
By  E.  W.  BEANS,  C.  E.     Illustrated.     I2mo.     Tucks.     .        $1.50 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


BELL. — Carpentry  Made  Easy: 

Or,   The  Science  and  Art  of  Framing  on  a'  New  and   Improved 
System.  With  Specific  Instructions  for  Building  Balloon  Frames,  Barn 
Frames,  Mill  Frames,  Warehouses,  Church  Spires,  etc.     Comprising 
also  a  System  of  Bridge  Building,  with  Bills,  Estimates  of  Cost,  and 
valuable  Tables.     Illustrated  by  forty-four  plates,  comprising  nearly 
200  figures.    By  WILLIAM  E.  BELL,  Architect  and  Practical  Builder. 
8vo.  .         .         .         .         .  .         .         .         .         $5.00 

BEMROSE. — Fret-Cutting  and  Perforated  Carving: 

With  fifty-three  practical  illustrations.     By  W.  BEMROSE,  JR.     I  vol. 

quarto $2.50 

BEMROSE. — Manual  of  Buhl-work  and  Marquetry: 

With  Practical  Instructions  for  Learners,  and  ninety  colored  designs, 
By  W.  BEMROSE,  JR.     i  vol.  quarto          ....        $3.00 

BEMROSE. — Manual  of  Wood  Carving: 

With  Practical  Illustrations  for  Learners  of  the  Art,  and  Original  and 
Selected   Designs.     By  WILLIAM  BEMROSE,   JR.     With   an   Intro- 
duction by  LLEWELLYN  JEWITT,  F.  S.  A.,  etc.     With  128  illustra- 
tions, 4to.  .........         $2.50 

BERSCH.— Cellulose,  Cellulose  Products,  and  Rubber  Sub- 
stitutes : 

Comprising     the    Preparation    of    Cellulose,    Parchment-Cellulose, 
Methods  of  Obtaining  Sugar,  Alcohol  and  Oxalic  Acid  from  Wood- 
Cellulose  ;     Production    of   Nitro-Cellulose    and    Cellulose    Esters ; 
Manufacture  of  Artificial  Silk,   Viscose,  Celluloid,   Rubber    Substi- 
tutes, Oil- Rubber,  and  Faktis.      By  DR.  JOSEPH  BERSCH.     Trans- 
lated by  WILLIAM  T.  BRANNT.     41  illustrations.      (1904.)     $3.00 
BILLINGS.— Tobacco : 

Its  History,  Variety,  Culture,  Manufacture,  Commerce,  and  Various 
Modes  of  Use.     By  E.   R.   BILLINGS.     Illustrated  by  nearly  200 
engravings.     8vo.      .          .          .          .          .          .  $3.00 

BIRD. — The  American  Practical  Dyers'  Companion  : 

Comprising  a  Description  of  the  Principal  Dye -Stuffs  and  Chemicals 
used  in  Dyeing,  their  Natures  and  Uses  ;  Mordants  and  How  Made  ; 
with  the  best  American,  English,  French  and  German  processes  for 
Bleaching  and  Dyeing  Silk,  Wool,  Cotton,  Linen,  Flannel,  Felt, 
Dress  Goods,  Mixed  and  Hosiery  Yarns,  Feathers,  Grass,  Felt,  Fur, 
Wool,  and  Straw  Hats,  Jute  Yarn,  Vegetable  Ivory,  Mats,  Skins, 
Furs,  Leather,  etc.,  etc.  By  Wood  Aniline,  and  other  Processes, 
together  with  Remarks  on  Finishing  Agents,  and  instructions  in  the 
Finishing  of  Fabrics,  Substitutes  for  Indigo,  Water-Proofing  of 
Materials,  Tests  and  Purification  of  Water,  Manufacture  of  Aniline 
and  other  New  Dye  Wares,  Harmonizing  Colors,  etc.,  etc.  ;  embrac- 
ing in  all  over  800  Receipts  for  Colors  and  Shades,  accompanied  by 
170  Dyed  Samples  of  Raw  Materials  and  Fabrics.  By  F.  J.  BIRD, 
Practical  Dyer,  Author  of  "The  Dyers'  Hand-Book."  8vo.  #7.50 


HENRY  CAREY   BAIRD  &  CO.'S  CATALOGUE 


BLINN.— A  Practical  Workshop  Companion  for  Tin,  Sheet- 

Iron,  and  Copper-plate  Workers : 

Containing  Rules  Tor  describing  various  kinds  of  Patterns  used  by 
Tin,  Sheet-Iron  and  Copper- plate  Workers;  Practical  Geometry; 
Mensuration  of  Surfaces  and  Solids;  Tables  of  the  Weights  of 
Metals,  Lead-pipe,  etc. ;  Tables  of  Areas  and  Circumference* 
of  Circles ;  Japan,  Varnishes,  Lackers,  Cements,  Compositions,  etc., 
etc.  By  LEROY  J.  BLINN,  Master  Mechanic.  With  One  Hundred 
and  Seventy  Illustrations.  I2mo ;  $2.50 

BOOTH.— Marble  Worker's  Manual: 

Containing  Practical  Information  respecting  Marbles  in  general,  theii 
Cutting,  Working  and  Polishing ;  Veneering  of  Marble  ;  Mosaics ; 
Composition  and  Use  of  Artificial  Marble,  Stuccos,  Cements,  Receipts, 
Secrets,  etc.,  etc.  Translated  from  the  French  by  M.  L.  BOOTH. 
With  an  Appendix  concerning  American  Marbles.  I2mo.,  cloth  $1.50 

BRAN  NT.— A    Practical   Treatise  on  Animal  and  Vegetabl« 

Fats  and  Oils : 

Comprising  both  Fixed  and  Volatile  Oils,  their  Physical  and  Chem- 
ical Properties  and  Uses,  the  Manner  of  Extracting  and  Refining 
them,  and  Practical  Rules  tor  Testing  them ;  as  well  as  the  Manufac- 
ture of  Artificial  Butter  and  Lubricants,  etc.,  with  lists  of  American 
Patents  relating  to  the  Extraction,  Rendering,  Refining,  Decomposing, 
and  Bleaching  of  Fats  and  Oils.  By  WILLIAM  T.  BRANNT,  Editor 
of  the  "  Techno-Chemical  Receipt  Book."  Second  Edition,  Revised 
and  in  a  great  port  Rewritten.  Illustrated  by  302  Engravings.  In 
Two  Volumes.  1304  pp.  8vo $10.00 

BRANNT.— A  Practical  Treatise  on  the  Manufacture  of  Soap 

and  Candles  : 

Based  upon  the  most  Recent  Experiences  in  the  Practice  and  Science ; 
comprising  the  Chemistry,  Raw  Materials,  Machinery,  and  Utensils 
and  Various  Processes  of  Manufacture,  including  a  great  variety  of 
formulas.  Edited  chiefly  from  the  German  of  Dr.  C.  Deite,  A. 
Engelhardt,  Dr.  C.  Schaedler  and  others;  with  additions  and  list? 
of  American  Patents  relating  to  these  subjects.  By  WM.  T.  BRANNT. 
Illustrated  by  163  engravings.  677  pages.  8vo.  .  .  $10.00 

BRANNT.— India  Rubber,  Gutta-Percha  and  Balata  : 

Occurrence,  Geographical  Distribution,  and  Cultivation,  Obtaining 
and  Preparing  the  Raw  Materials,  Modes  of  Working  and  Utilizing 
them,  Including  Washing,  Maceration,  Mixing,  Vulcanizing, Rubber 
and  Gutta-Percha  Compounds,  Utilization  of  Waste,  etc.  By  WILL- 
IAM T.  BRANNT.  Illustrated.  i2mo.  (1900.)  .  . 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


BRANNT— WAHL.— The  Techno-Chemical  Receipt  Book: 

Containing  several  thousand  Receipts  covering  the  latest,  most  im- 
portant, and  most  useful  discoveries  in  Chemical  Technology,  and 
their  Practical  Application  in  the  Arts  and  the  Industries.  Edited 
chiefly  from  the  German  of  Drs.  Winckler,  Eisner,  Heintze,  Mier- 
zinski,  Jacobsen,  Koller  and  Heinzerling,  with  additions  by  WM.  T. 
BRANNT  and  WM.  H.  WAHL,  Ph.  D.  Illustrated  by  78  engravings. 
I2mo.  495  pages $2.00 

BROWN. — Five  Hundred  and  Seven  Mechanical  Movements  : 
Embracing  all  those  which  are  most  important  in  Dynamics,  Hy- 
draulics, Hydrostatics,  Pneumatics,  Steam  Engines,  Mill  and  other 
Gearing,  Presses,  Horology,  and  Miscellaneous  Machinery  ;  and  in- 
cluding many  movements  never  before  published,  and  several  of 
which  have  only  recently  come  into  use.  By  HENRY  T.  BROWN. 
I2mo $1.00 

8UCKMASTER. — The  Elements  of  Mechanical  Physics : 
By  J.   C.   BUCKMASTER.       Illustrated    with    numerous    engravings. 
I2mo .'•*--"    .         $1.00 

BULLOCK. — The  American  Cottage  Builder  : 
A  Series  of  Designs,  Plans  and  Specifications,  from  $200  to  ,$20,000, 
for  Homes  for  the  People ;  together  with  Warming,  Ventilation, 
Drainage,  Painting  and  Landscape  Gardening.  By  JOHN  BULLOCK, 
Architect  and  Editor  of  "  The  Rudiments  of  Architecture  and 
Building,"  etc.,  etc.  Illustrated  by  75  engravings.  8vo.  $2.50 

BULLOCK. — The  Rudiments  of  Architecture  and  Building: 
For  the  use  of  Architects,   Builders,   Draughtsmen,   Machinists,  En- 
gineers and  Mechanics.     Edited  by  JOHN  BULLOCK,  author  of  "  The 
American  Cottage  Builder."   Illustrated  by  250  Engravings.  8vo.  $2.50 

8URGH. — Practical    Rules    for    the   Proportions   of     Modern 

Engines  and  Boilers  for  Land  and  Marine  Purposes. 
By  N.  P.  BURGH,  Engineer.     I2mo.          ....         $1.50 

BYLES. — Sophisms    of    Free    Trade   and    Popular    Political 

Economy  Examined. 

By  a  BARRISTER  (SiR  JOHN  BARNARD  BYLES,  Judge  of  Common 
Pleas).  From  the  Ninth  English  Edition,  as  published  by  the 
Manchester  Reciprocity  Association.  I2mo.  .  .  .  $1.25 

BOWMAN. — The  Structure  of  the  Wool  Fibre  in  its  Relation 

to  the  Use  of  Wool  for  Technical  Purposes: 
Being  the  substance,  with  additions,  of  Five  Lectures,  delivered  at 
the  request  of  the  Council,  to  the  members  of  the  Bradford  Technical 
College,  and  the  Society  of  Dyers  and  Colorists.  By  F.  H.  BOW- 
MAN, D.  Sc.,  F.  R.  S.  E.,  F.  L.  S.  Illustrated  by  32  engravings. 
8vo #7-5° 

BYRNE. — Hand-Book  for  the  Artisan,  Mechanic,  and  Engi- 
neer: 

Comprising  the  Grinding  and  Sharpening  of  Cutting  Tools,  Abrasive 
Processes,  Lapidary  Work,  Gem  and  Glass  Engraving,  Varnishing 
and  Lackering,  Apparatus,  Materials  and  Processes  for  Grinding  and 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


Polishing,  etc.  By  OLIVER  BYRNE.  Illustrated  by  185  wood  en- 
gravings. 8vo. $5.00 

8YRNE.— Pocket-Book  for  Railroad  and  Civil  Engineers: 
Containing  New,  Exact  and  Concise  Methods  for  Laying  out  Railroad 
Curves,  Switches,  Frog  Angles  and  Crossings ;  the  Staking  out  of 
work  ;  Levelling ;  the  Calculation  of  Cuttings :  Embankments ;  Earth- 
work, etc.  By  OLIVER  BYRNE.  i8mo.,  full  bound,  pocket-book 
form $1.50 

BYRNE. — Tne  Practical  Metal- Worker's  Assistant: 

Comprising  Metallurgic  Chemistry;  the  Arts  of  Working  all  Metalf 
and  Alloys ;  Forging  of  Iron  and  Steel ;  Hardening  and  Tempering; 
Melting  and  Mixing;  Casting  and  Founding  ;  Works  in  Sheet  Metal; 
the  Processes  Dependent  on  the  Ductility  of  the  Metals;  Soldering; 
and  the  most  Improved  Processes  and  Tools  employed  by  Metal- 
workers. With  the  Application  of  the  Art  of  Electro- Metallurgy  to 
Manufacturing  Processes ;  collected  from  Original  Sources,  and  from 
the  works  of  Holtzapffel,  Bergeron,  Leupold,  Piumier,  Napier, 
Scoffern,  Clay,  Fairbairn  and  others.  By  OLIVER  BYRNE.  A  new, 
revised  and  improved  edition,  to  which  is  added  an  Appendix,  con- 
taining  The  Manufacture  of  Russian  Sheet- Iron.  By  JOHN  PERCY, 
M.  D.,  F.  R.  S.  The  Manufacture  of  Malleable  Iron  Castings,  and 
Improvements  in  Bessemer  Steel.  By  A.  A.  FESQUET,  Chemist  and 
Engineer.  With  over  Six  Hundred  Engravings,  Illustrating  every 
Branch  of  the  Subject.  8vo £5.00 

BYRNE.— The  Practical  Model  Calculator: 

For  the  Engineer,  Mcchan.c,  Manufacturer  of  Engine  Work,  Narai 
Architect,  Miner  and  Millwright.  By  OLIVER  BYRNE.  8vo.,  nearly 
600  pages .  (Scarce.) 

CABINET  MAKER'S  ALBUM  OF  FURNITURE". 

Comprising  a  Collection  of  Designs  for  various  Styles  of  Furniture. 
Illustrated  by  Forty-eight  Large  and  Beautifully  Engraved  Plates. 
Oblong,  8vo.  .....  ..~"  .  .  Si. 50 

CALLINGHAM.— Sign  Writing  and  Glass  Embossing: 

A  Complete  Practical  Illustrated  Manual  of  the  Art.  By  JAMES 
CALLINGHAM.  To  which  are  added  Numerous  Alphabets  and  the 
Art  of  Letter  Painting  Made  Easy.  By  JAMES  C.  BADENOCH.  258 
pages.  I2mo. |i-5O 

CAMPIN.— A  Practical  Treatise  on  Mechanical  Engineering: 
Comprising  Metallurgy,  Moulding,  Casting,  Forging,  Tools,  Work, 
shop  Machinery,  Mechanical  Manipulation,  Manufacture  of  Steam* 
Engines,  etc.  With  an  Appendix  on  the  Analysis  of  Iron  and  Iron 
Ores.  By  FRANCIS  CAMPIN,  C.  E.  To  which  are  added,  Observations 
on  the  Construction  of  Steam  Boilers,  and  Remarks  upon  Furnaces 
used  for  Smoke  Prevention ;  with  a  Chapter  on  Explosions.  By  R. 
ARMSTRONG,  C.  E.,  and  JOHN  BOURNE.  (Scarce.) 


HENRY  CAREY  BAIRD  &  CG.'S  CATALOGUE. 


CAREY. — A  Memoir  of  Henry  C.  Carey. 
By  DR.  WM.  ELDER.    With  a  portrait.     8vo.,  cloth         .        .        75 

CAREY.— The  Works  of  Henry  C.  Carey : 

Harmony  of  Interests  :    Agricultural,  Manufacturing  and  Commer- 
cial.    8vo.  .....  .  $^.25' 

Manual  of  Social  Science.  Condensed  from  Carey's  "  Principles 
of  Social  Science."  By  KATE  McKEAN.  i  vol.  I2mo.  .  $2.00 
Miscellaneous  Works.  With  a  Portrait.  2  vols.  8vo.  $10.00  ( 

Past,  Present  and  Future.     8vo $2.50) 

Principles  of  Social  Science.  3  volumes,  8vo.  .  .  $7.50 
The  Slave-Trade,  Domestic  and  Foreign;  Why  it  Exists,  and 
How  it  may  be  Extinguished  (1853).  8vo.  .  .  .  $2.00 
The  Unity  of  Law :  As  Exhibited  in  the  Relations  of  Physical, 
Social,  Mental  and  Moral  Science  (1872).  8vo.  .  .  $2.50 

CLARK. — Tramways,  their  Construction  and  Working : 

Embracing  a  Comprehensive  History  of  the  System.  With  an  ex- 
haustive  analysis  of  the  various  modes  of  traction,  including  horse- 
power, steam,  heated  water  and  compressed  air;  a  description  of  the 
varieties  of  Rolling  stock,  and  ample  details  of  cost  and  working  ex- 
penses. By  D.  KINNEAR  CLARK.  Illustrated  by  over  200  wood 
engravings,  and  thirteen  folding  plates.  I  vol.  8vo.  .  $5.00 

COLBURN. — The  Locomotive  Engine  : 

Including  a  Description  of  its  Structure,  Rules  for  Estimating  its 
Capabilities,  and  Practical  Observations  on  its  Construction  and  Man- 
agement. By  ZERAH  COLBURN.  Illustrated.  I2mo.  .  $1.00 

COLLENS. — The  Eden  of  Labor;  or,  the  Christian  Utopia. 
By  T.  WHARTON  COLLENS,  author  of  "  Humanics,"   "  The  Historj 
of  Charity,"  etc.     I2mo.     Paper  cover,  $  i.  oo;  Cloth          .         $1.25 

COOLEY. — A  Complete  Practical  Treatise  on  Perfumery: 
Being  a  Hand-book  of  Perfumes,  Cosmetics  and  other  Toilet  Articlei 
With   a  Comprehensive    Collection  of  Formulae.     By   ARNOLD  J, 
COOLEY.    I2mo.        .         .        .        »        .        .        .         .        $1.50 

COOPER. — A  Treatise  on  the  use  of  Belting  for  the  TranL- 

mission  of  Power. 

With  numerous  illustrations  of  approved  and  actual  methods  of  ar- 
ranging Main  Driving  and  Quarter  Twist  Belts,  and  of  Belt  Fasten 
ings.  Examples  and  Rules  in  great  number  for  exhibiting  and  cal- 
culating the  size  and  driving  power  of  Belts.  Plain,  Particular  and 
Practical  Directions  for  the  Treatment,  Care  and  Management  or 
Belts.  Descriptions  of  many  varieties  of  Beltings,  together  witn 
chapters  on  the  Transmission  of  Power  by  Ropes;  by  Iron  and 
Wood  Frictional  Gearing ;  on  the  Strength  of  Belting  Leather ;  and 
on  the  Experimental  Investigations  of  Morin,  Briggs,  and  others.  By 
JOHN  H.  COOPER,  M.  E.  8vo $3«5<> 

CRAIK. — The  Practical  American  Millwright  and  MUler. 
By  DAVID  CRAIK,  Millwright.     Illustrated  by  numerous  wood  en 
gravings  and  two  folding  plates.     8vo.  .        .  (Scarce.) 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.  9 

CROSS. — The  Cotton  Yarn  Spinner: 

Showing  how  the  Preparation  should  be  arranged  for  Different 
Counts  of  Yarns  by  a  System  more  uniform  than  has  hitherto  been 
practiced ;  by  having  a  Standard  Schedule  from  which  we  make  all 
our  Changes.  By  RICHARD  CROSS.  122  pp.  I2mo.  .  75 

CRISTIANI. —  A  Technical  Treatise  on  Soap  and  Candles: 
With  a  Glance  at  the  Industry  of  Fats  and  Oils.     By  R.  S.  CRIS- 
TIANI, Chemist.     Author  of  "  Perfumery  and  Kindred  Arts."     Illus- 
trated by  176  engravings.     581  pages,  8vo.  #15.00 

COURTNEY. — The  Boiler  Maker's  Assistant  in  Drawing, 
Templating,  and  Calculating  Boiler  Work  and  Tank 
Work,  etc. 

Revised  by  D.  K.  CLARK.     102  ills.     Fifth  edition.      .         .         80 
COURTNEY.— The  Boiler  Maker's  Ready  Reckoner: 

With  Examples  of  Practical  Geometry  and  Templating.  Revised  by 
D.  K.  CLARK,  C.  E.  37  illustrations.  Fifth  edition.  •  $1.60 

DAVIDSON. — A  Practical  Manual  of  House  Painting,  Grain- 
ing, Marbling,  and  Sign- Writing: 

Containing  full  information  on  the  processes  of  House  Painting  in 
Oil  and  Distemper,  the  Formation  of  Letters  and  Practice  of  Sign- 
Writing,  the  Principles  of  Decorative  Art,  a  Course  of  Elementary 
Drawing  for  House  Painters,  Writers,  etc.,  and  a  Collection  of  Useful 
Receipts.  With  nine  colored  illustrations  of  Woods  and  Marbles, 
and  numerous  wood  engravings.  By  ELLIS  A.  DAVIDSON.  I2mo. 

$2.00 

DAVIES.— A  Treatise  on  Earthy  and  Other    Minerals   and 

Mining: 

By  D.  C.  DAVIES,  F.  G.  S.,  Mining  Engineer,  etc.  Illustrated  by 
76  Engravings.  I2mo $$.OO 

DAVIES. — A  Treatise  on  Metalliferous  Minerals  and  Mining: 
By  D.  C.  DAVIES,  F.  G.  S  ,  Mining  Engineer,  Examiner  of  Mines, 
Quarries  and  Collieries.  Illustrated  by  148  engravings  of  Geological 
Formations,  Mining  Operations  and  Machinery,  drawn  from  the 
practice  of  all  parts  of  the  world.  Fifth  Edition,  thoroughly  Revised 
and  much  Enlarged  by  his  son,  E.  Henry  Davies.  I2mo.,  524 
pages ,  .  '  .  .  $5.00 

DAVIES. — A  Treatise  on  Slate  and  Slate  Quarrying: 

Scientific,  Practical  and  Commercial.  By  D.  C.  DAVIES,  F.  G.  S., 
Mining  Engineer,  etc.  With  numerous  illustrations  and  folding 
plates.  J2mo. $1.20 

DAVIS.— A  Practical  Treatise  on  the  Manufacture  of  Brick, 

Tiles  and  Terra-Cotta : 

Including  Stiff  Clay,  Dry  Clay,  Hand  Made,  Pressed  or  Front,  and 
Roadway  Paving  Brick,  Enamelled  Brick,  with  Glazes  and  Colors, 
Fire  Brick  and  ^Blocks.  Silica  Brick,  Carbon  Brick,  Glass  Pots,  Re- 


jo          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGS. 

torts,  Architectural  Terra-Cotta,  Sewer  Pipe,  Drain  Tile,  Glazed  and 
Unglazed  Roofing  Tile,  Art  Tile,  Mosaics,  and  Imitation  of  Intarsia 
or  Inlaid  Surfaces.     Comprising  every  product  of  Clay  employed  in 
Architecture,  Engineering,  and  the  Blast  Furnace.     With  a  Detailed 
Description    of  the    Different    Clays    employed,   the    Most    Modern 
Machinery,  Tools,  and  Kilns  used,  and  the  Processes  for  Handling, 
Disintegrating,  Tempering,  and  Moulding  the  Clay  into  Shape,  Dry- 
ing, Setting,  and  Burning.      By  Charles  Thomas  Davis.     Third  Edi- 
tion.    Revised    and    in   great    part   rewritten.     Illustrated    by    261 
engravings.     662  pages     .......      $12.50 

DAVIS. — A  Treatise  on  Steam-Boiler  Incrustation  and  Meth- 
ods for  Preventing  Corrosion  and  the  Formation  of  Scale: 
By  CHARLES  T.  DAVIS.     Illustrated  by  65  engravings.     8vo. 
DAVIS.— The  Manufacture  of  Paper: 

Being  a  Description  of  the  various   Processes  for  the  Fabrication, 
Coloring  and  Finishing  of  every  kind  of  Paper,  Including  the  Dif- 
ferent Raw  Materials  and  the  Methods  for  Determining  their  Values, 
the  Tools,  Machines  and  Practical  Details  connected  with  an  intelli- 
gent and  a  profitable  prosecution  of  the  art,  with  special  reference  to 
the  best  American  Practice.     To  which  are  added  a  History  of  Pa- 
per, complete  Lists  of  Paper-Making  Materials,  List  of  American 
Machines,  Tools  and  Processes  used  in  treating  the  Raw  Materials, 
and  in  Making,  Coloring  and  Finishing  Paper.     By  CHARLES  T. 
DAVIS.     Illustrated  by  156  engravings.     608  pages,  8vo.          $6.00 
DAVIS. — The  Manufacture  of  Leather: 

Being  a  Description  of  all  the  Processes  for  the  Tanning  and  Tawing 
•with  Bark,  Extracts,  Chrome  and   all   Modern   Tannages  in  General 
Use,  and  the  Currying,  Finishing  and  Dyeing  of  Every  Kind  of  Leather; 
Including  the  Various  Raw  Materials,  the  Tools,  Machines,  and  all 
Details  of  Importance  Connected  with  an  Intelligent  and  Profitable 
Prosecution  of  the  Art,  with  Special   Reference  to  the  Best  American 
Practice.     To  which  are  added  Lists  of  American  Patents  (1884-1897) 
for  Materials,  Processes,  Tools  and  Machines  for  Tanning,  Currying, 
etc.     By  CHARLES  THOMAS  DAVIS.     Second  Edition,  Revised,  and 
in  great  part  Rewritten.     Illustrated  by  147  engravings  and  14  Sam- 
ples of  Quebracho  Tanned  and  Aniline  Dyed  Leathers.     8vo,  cloth, 
712  pages.     Price     .         .        '.         i" "     :; '  '    .         ,' •      .      $10.00 
DAWIDOWSKY— BRANNT.— A   Practical  Treatise  on  the 
Raw  Materials  and  Fabrication  of  Glue,  Gelatine,  Gelatine 
Veneers  and  Foils,  Isinglass,  Cements,  Pastes,  Mucilages, 
etc. : 

Based  upon  Actual  Experience.     By  F.  DAWIDOWSKY,  Technical 
Chemist.     Translated   from  the   German,  with   extensive  additions, 
including  a  description  of  the  most  Recent  American  Processes,  by 
WILLIAM   T.    BRANNT.       2d  revised  edition,  350  pages.        (1905.) 
Price       ..........        $3.00 

DE  GRAFF. — The  Geometrical  Stair-Builders'  Guide : 

Being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all  its 
necessary  Details,  and  Geometrically  Illustrated  by  twenty-two  Stee 
Engravings;  together  with  the  use  of  the  most  approved  principle 
of  Practical  Geometry  By  SIMON  DE  GRAFF,  Architect  (scarce. » 


HENRY   CAREY   BAIRD   &   CO.'S   CATALOGUE.        n 

DE  KONINCK— DIETZ.— A  Practical  Manual  of  Chemica 

Analysis  and  Assaying : 

As  applied  to  the  Manufacture  of  Iron  from  its  Ores,  and  to  Cast  Iron, 
Wrought  Iron,  and  Steel,  as  found  in  Commerce.  By  L.  L.  DB 
KONINCK,  Dr.  Sc.,  and  E.  DIETZ,  Engineer.  Edited  with  Notes,  by 
ROBERT  MALLET,  F.  R.  S.,  F.  S.  G.,  M.  I.  C.  E.,  etc.  American 
Edition,  Edited  with  Notes  and  an  Appendix  on  Iron  Ores,  by  A.  A. 
FESQUET,  Chemist  and  Engineer.  I2mo.  .  .  .  $1.50 

UNCAN.— Practical  Surveyor's  Guide: 

Containing  the  necessary  information  to  make  any  person  of  corm 
mon  capacity,  a  finished  land  surveyor  without  the  aid  of  a  teacher. 
By  ANDREW  DUNCAN.  Revised.  72  engravings,  214pp.  I2mo.  £1.50 

DUPLAIS. — A  Treatise  on  the   Manufacture  and  Distillation 

of  Alcoholic  Liquors : 

Comprising  Accurate  and  Complete  Details  in  Regard  to  Alcohol 
from  Wine,  Molasses,  Beets,  Grain,  Rice,  Potatoes,  Sorghum,  Aspho 
del,  Fruits,  etc. ;  with  the  Distillation  and  Rectification  of  Brandy, 
Whiskey,  Rum,  Gin,  Swiss  Absinthe,  etc.,  the  Preparation  of  Aro* 
matic  Waters,  Volatile  Oils  or  Essences,  Sugars,  Syrups,  Aromatic 
Tinctures,  Liqueurs,  Cordial  Wines,  Effervescing  Wines,  etc..  the 
Ageing  of  Brandy  and  the  improvement  of  Spirits,  with  Copious 
Directions  and  Tables  for  Testing  and  Reducing  Spirituous  Liquors, 
etc..*  etc.  Translated  and  Edited  from  the  French  of  MM.  DUPLAIS, 
By  M.  McKENNiE,  M.  D.  Illustrated  743  pp.  8vo.  $15.00 

DYER  AND  COLOR-MAKER'S  COMPANION: 

Containing, upwards  of  two  hundred  Receipts  for  making  Colors,  on 
the  most  approved  principles,  for  all  the  various  styles  and  fabrics  now 
in  evistence ;  with  the  Scouring  Process,  and  plain  Directions  for 
Preparing,  Washing-oft",  and  Finishing  the  Goods.  I2mo.  $i  oo 

EIDHERR. — The  Techno-Chemical  Guide  to  Distillation: 
A  Hand-Book  for  the  Manufacture  of  Alcohol  and  Alcoholic  Liquors, 
including  the  Preparation  of  Malt  and  Compressed  Yeast.     Edited 
from  the  German  of  Ed.  Eidherr. 

EDWARDS.— A  Catechism  of  the  Marine  Steam-Engine, 
For  the  use  of  Engineers,  Firemen,  and  Mechanics.  A  Practical 
Work  for  Practical  Men.  By  EMORY  EDWARDS,  Mechanical  Engi- 
neer. Illustrated  by  sixty-three  Engravingss  including  examples  of 
the  most  modern  Engines.  Third  edition,  thoroughly  revised,  with 
much  additional  matter.  1 2  mo.  414  pages  .  .  .  $2  oo 

EDWARDS. — Modern  American  Locomotive  Engines, 
Their  Design,  Construction  and  Management.     By  EMORY  EDWARDS* 
Illustrated  I2mo $2.00 

EDWARDS.— The  American  Steam  Engineer: 
Theoretical  and  Practical,  with  examples  of  the  latew*;  and  most  ap- 
proved American  practice  in  the  design  and  construction  of  Steam 
Engines  and  Boilers.  For  the  use  of  engineers,  machinists,  boiler- 
makers,  and  engineering  students.  By  EMORY  EDWARDS.  Fully 
illustrated,  419  pages.  I2mo.  ~*  *  ...  |2JJO 


12         HENRY  CAREY  BAIRD  &  CO.'S   CATALOGUE. 

EDWARDS. — Modern  American  Marine  Engines,  Boilers,  and 

Screw  Propellers, 

Their  Design  and   Construction.     Showing  the  Present   Practice  ot 
the  most   Eminent   Engineers  and   Marine  Engine  Builders  in  the 
United  States.    Illustrated  by  30  large  and  elaborate  plates.  4to.  $5.00 
EDWARDS. — The  Practical  Steam  Engineer's  Guide 

In  the  Design,  Construction,  and  Management  of  American  Stationary, 
Portable,  and  Steam  Fire- Engines,  Steam   Pumps,  Boilers,  Injector^  j 
Governors,  Indicators,  Pistons  and  Rings,  Safety  Valves  and   Steam 
Gauges.     For  the  use  of  Engineers,  Firemen,  and  Steam  Users.    B) 
EMORY   EDWARDS.      Illustrated  by    119  engravings.    A2O    pages, 

I2mo $2  50 

EISSLER. — The  Metallurgy  of  Silver  : 

A  Practical  Treatise  on  the  Amalgamation,  Roasting,  and  Lixiviation 
of  Silver  Ores,  including   the  Assaying,   Melting,  and  Refining  of 
Silver    Bullion.     By    M.    EISSLER.     124    Illustrations.      336    pp. 
I2mo.       .         .         .         f       •>.    .    .         .         .         .         .         $4-25 

ELDER. — Conversations  on  the  Principal  Subjects  of  Political 

Economy. 

By  DR.  WILLIAM  ELDER.     8vo.       .        .V  •        #2  5° 

ELDER. — Questions  of  the  Day, 

Economic  and  Social.     By  DR.  WILLIAM  ELDER.     8vo.      .     $3.00 
ERNI  AND  BROWN.— Mineralogy  Simplified. 

Easy  Methods  of  Identifying  Minerals,  including  Ores,  by  Means  of 
the  Blow -pipe,  by  Flame  Reactions,  by  Humid  Chemical  Analysis, 
and  by  Physical  Tests.      By  HENRI  ERNI,  A.  M.,  M.  D.     Third  Edi- 
tion, revised,  re-arranged  and  with  the  addition  of  entirely  new  matter, 
including  Tables  for  the  Determination  of  Minerals  by  Chemical  and 
Pyrognostic   Characters,  and  by  Physical  Characters.     By  AMOS  P. 
BROWN,  E.  M.,  Ph.  D.    350  pp.,  illustrated  by  96  engravings,  pocket- 
book  form,  full  flexible  morocco,  gilt  edges       .         .         .         $2.50 
FAIRBAIRN.  -The  Principles  of  Mechanism  and  Machinery 

of  Transmission  : 

Comprising    the    Principles    of  Mechanism,   Wheels,    and    Pulleys, 
Strength  and  Proportion  of  Shafts,  Coupling  of  Shafts,  and  Engag- 
ing and   Disengaging   Gear.     By   SIR  WILLIAM  FAIRBAIRN,  Bart. 
C.    E.       Beautifully    illustrated   by   over    150   wood-cuts.      In   one 
volume,  I2mo.         .        ...          .          .          .  -  :  -  .*•         .         $2.00 

FLEMING. — Narrow  Gauge  Railways  in  America  : 

A  Sketch  of  their  Rise,  Progress,  and  Success.     Valuable  Statistics 
as  to  Grades,  Curves,  Weight  of  Rail,  Locomotives,  Cars,  etc.     By 

HOWARD  FLEMING.     Illustrated,  8vo $1.00 

FORSYTH. — Book  of  Designs  for  Headstones,  Mural,  and 

other  Monuments  : 

Containing  78  Designs.     By  JAMES  FORSYTH,    With  an  Introduction 
by  CHARLES  BOUTELL,  M.  A.     410.,  cloth       .         .         .         $3.50 
FRIEDBERG.     Utilization  of  Bones   by  Chemical   Means; 
especially  the  Modes  of  Obtaining   Fat,  Glue,  Manures, 
Phosphorus  and  Phosphates. 
Illustrated.     8vo.      (In  preparation. ) 


HENRY   CAREY    BAIRD   &   CO.'S   CATALOGUE.        13 


FRANKEL— HUTTER.— A  Practical  Treatise  on  the  Manu« 

facture  of  Starch,  Glucose,  Starch-Sugar,  and  Dextrine: 
Based  on  the  German  of  LADISLAUS  VON  WAGNER,  Professor  in  the 
Royal  Technical  High  School,  Buda-Pest,  Hungary,  and  other 
authorities.  By  JULIUS  FRANKEL,  Graduate  of  the  Polytechnic 
School  of  Hanover.  Edited  by  ROBERT  HUTTER,  Chemist,  Practical 
Manufacturer  of  Starch-Sugar.  Illustrated  by  58  engravings,  cover- 
ing every  branch  of  the  subject,  including  examples  of  the  most 
Recent  and  Best  American  Machinery.  8vo.,  344  pp.  $6.00 

GARDNER. — The  Painter's  Encyclopaedia: 
Containing  Definitions  of  all  Important  Words  in  the  Art  of  Plain 
and  Artistic  Painting,  with  Details  of  Practice  in  Coach,  Carriage, 
Railway  Car,  House,  Sign,  and  Ornamental  Painting,  including 
Graining,  Marbling,  Staining.  Varnishing,  Polishing,  Lettering, 
Stenciling,  Gilding,  Bronzing,  etc.  By  FRANKLIN  B.  GARDNER. 
158  Illustrations.  I2mo.  427  pp.  .....  $2.OC 

GARDNER.— Everybody's  Paint  Book: 

A  Complete  Guide  to  the  Art  of  Outdoor  and  Indoor  Painting.  38 
illustrations.  I2mo,  183  pp $1.00 

GEE.— The   Jeweller's    Assistant  in  the    Art  of  Working  in 

Gold: 
A  Practical  Treatise  for  Masters  and  Workmen.     121110.      .       $4.00 

GEE. — The  Goldsmith's  Handbook : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Gold, 
including  the  Art  of  Alloying,  Melting,  Reducing,  Coloring,  Col- 
lecting,  and  Refining;  the  Processes  of  Manipulation,  Recovery  of 
Waste;  Chemical  and  Physical  Properties  of  Gold;  with  a  New 
System  of  Mixing  its  Alloys ;  Solders,  Enamels,  and  other  Useful 
Rules  and  Recipes.  By  GEORGE  E.  GEE.  I2mo.  .  .  £1.25 

GEE. — The  Silversmith's  Handbook  : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Silver, 
including  the  different  modes  of  Refining  and  Melting  the  Metal ;  its 
Solders ;  the  Preparation  of  Imitation  Alloys ;  Methods  of  Manipula- 
tion ;  Prevention  of  Waste ;  Instructions  for  Improving  and  Finishing 
the  Surface  of  the  Work ;  together  with  other  Useful  Information  and 
Memoranda.  By  GEORGE  E.  GEE.  Illustrated.  I2mo.  $1.25 

GOTHIC  ALBUM  FOR  CABINET-MAKERS: 

Designs  for  Gothic  Furniture.     Twenty-three  plates.     Oblong  #1.5° 

GRANT. — A  Handbook  on  the  Teeth  of  Gears  : 
Their  Curves,  Properties,  and  Practical  Construction.     By  GEORGE 
B.  GRANT.     Illustrated.     Third  Edition,  enlarged.     8vo.          #1.00 

GREENWOOD.— Steel  and  Iron: 

Comprising  the  Practice  and  Theory  of  the  Several  Methods  Pur- 
sued in  their  Manufacture,  and  of  their  Treatment  in  the  Rolliug- 
Mills,  the  Forge,  and  the  Foundry.  By  WILLIAM  HENRY  GREEN- 
WOOD, F.  C.  S.  With  97  Diagrams,  536  pages.  I2mo.  $1.75 


14       HENRY   CAREY   BAIRD   &   CO.'S  CATALOGUE 


GREGORY. — Mathematics  for  Practical  Men : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics,  and 
Civil  Engineers.  By  OLINTHUS  GREGORY.  8vo.,  plates  $3.00 

GRISWOLD. — Railroad  Engineer's  Pocket  Companion  for  tin 

Field : 

Comprising  Rules  for  Calculating  Deflection  Distances  and  Angles, 
Tangential  Distances  and  Angles,  and  all  Necessary  Tables  for  En 
gineers;  also  the  Art  of  Levelling  from  Preliminary  Survey  to  the 
Construction  t>f  Railroads,  intended  Expressly  for  the  Young  En- 
gineer, together  with  Numerous  Valuable  Rules  and  Examples.  By 
W.  GRISWOLD.  i2mo.,  tucks $1.50 

"GRUNER. — Studies  of  Blast  Furnace  Phenomena: 

By  M.  L.  GRUNER,  President  of  the  General  Council  of  Mines  o$ 
France,  and  lately  Professor  of  Metallurgy  at  the  Ecole  des  Mines. 
Translated,  with  the  author's  sanction,  with  an  Appendix,  by  L.  D. 
B.  GORDON,  F.  R.  S.  E.,  F.  G.  S.  8vo.  .  .  .  $2.50 

Hand-Book  of  Useful  Tables  for  the  Lumberman,  Farmer  and 

Mechanic : 

Containing  Accurate  Tables  of  Logs  Reduced  to  Inch  Board  Meas. 
ure,  Plank,  Scantling  and  Timber  Measure ;  Wages  and  Rent,  by 
Week  or  Month;  Capacity  of  Granaries,  Bins  and  Cisterns;  Land 
Measure,  Interest  Tables,  with  Directions  for  Finding  the  Interest  on 
any  sum  at  4,  5,  6,  7  and  8  per  cent.,  and  many  other  Useful  Tables. 
32  mo.,  boards.  1 86  pages .25 

HASERICK.— The  Secrets  of  the  Art  of  Dyeing  Wool,  Cotton, 

and  Linen, 

Including  Bleach:rg  an/i  Coloring  Wool  and  Cotton  Hosiery  and 
Random  Yarns.  A  Treatise  based  on  Economy  and  Practice.  By 
E.  C.  HASERICK.  Illustrated  by  323  Dyed  Patterns  of  the  Yarn\ 
or  Fabrics.  8vo #5-OO 

HATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.  By  a  Practical  Hatter, 
Illustrated  by  Drawings  of  Machinery,  etc.  8vo.  .  .  $1.00 

HERMANN. — Painting  on  Glass  and  Porcelain,  and  Enamel 

Painting: 

A  Complete  Introduction  to  the  Preparation  of  all  the  Colors  and 
Fluxes  Used  for  Painting  on  Glass,  Porcelain,  Enamel,  Faience  and 
Stoneware,  the  Color  Pastes  and  Colored  Glasses,  together  with  a 
Minute  Description  ot  the  Firing  ot  Colors  and  Enamels,  on  the 
Basis  of  Personal  Practical  Experience  of  the  Art  up  to  Date.  18 
illustrations.  Second  edition.  .  .  .  . 

HAUPT.— Street  Railway  Motors: 

With  Descriptions  and  Cost  of  Plants  and  Operation  of  the  Various 
Systems  now  in  Use.  I2tM^. '  •  .  >  .  $1-75 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.         15 

HAUPT. — A  Manual  of  Engineering  Specifications  and  Con- 
tracts. 

By  LEWIS  M.  HAUPT,  C.  E.  Illustrated  with  numerous  maps. 
328pp.  8vo £3  oo 

HAUPT.— The  Topographer,  His  Instruments  and  Methods. 
By  LEWIS  M.  HAUPT,  A.  M.,  C.  E.  Illustrated  with  numerous 
plates,  maps  and  engravings.  247  pp.  8vo.  .  .  .  $3.00 

HUGHES. — American  Miller  and  Millwright's  Assistant: 
By  WILLIAM  CARTER  "HUGHES.    i2mo.     ....        $1.50 

HULME. — Worked  Examination  Questions  in  Plane  Geomet- 
rical Drawing  : 

For  the  Use  of  Candidates  for  the  Royal  Military  Academy,  Wool- 
wich;  the  Royal  Military  College,  Sandhurst ;  the  Indian  Civil  En- 
gineering  College,  Cooper's  Hill  ;  Indian  Public  Works  and  Tele- 
graph Departments;  Royal  Marine  Lit:ht  Infantry;  the  Oxford  and 
Cambridge  Local  Examinations,  etc.  By  F.  EDWARD  HULME,  F.  L. 
S.,  F.  S.  A.,  Art-Master  Marlborough  College.  Illustrated  by  300 
examples.  Small  quarto Jl.$ 

JEK VIS. —Railroad  Property: 

A  Treatise  on  the  Construction  and  Management  of  Railways; 
designed  to  afford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property ;  as  well  as  Railway  Managers,  Offi 
cers,  and  Agents.  By  JOHN  B.  JERVIS,  late  Civil  Engineer  of  the 
Hudson  River  Railroad,  Croton  Aqueduct,  etc.  i2mo.,  cloth  $1.50 

KEENE.— A  Hand-Book  of  Practical  Gauging: 
For  the  Use  of  Beginners,  to  which  is  added  a  Chapter  on  Distilla- 
tion, describing  the  process  in   operation  at  the  Custom- House  fof 
ascertaining  the  Strength  of  Wines.     By  JAMES  B.  KEENE,  of  H.  M. 
Customs.     8vo. $l  oc 

KELLEY.— Speeches,  Addresses,  and  Letters  on  Industrial  and 

Financial  Questions : 
By  HON.  WILLIAM  D.  KELLEY,  M.  C.     544  pages,  8vo.  .        $2.50 

KELLOGG.— A  New  Monetary  System  : 

The  only  means  of  Securing  the  respective  Rights  of  Labor  and 
Property,  and  of  Protecting  the  Public  from  Financial  Revulsions. 
By  EDWARD  KELLOGG.  121110.  Paper  cover,  $1.00.  Bound  m 
cloth $''25 

KEMLO.— Watch- Repairer's  Hand-Book : 
Being  a  Complete  Guide  to  the  Young  Beginner,  in  Taking  Apart 
Putting  Together,  and  Thoroughly  Cleaning  the  English  Lever  and 
other  .Foreign  Watches,  and  all  American  Watches.     By  F.  KEMLO, 
Nactical  Watchmaker.     With  Illustrations.     12010.  $1-25 


t6          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

KENTISH.; — A  Treatise  on  a  Box  of  Instruments, 

And  the  Slide  Rule ;  with  the  Theory  of  Trigonometry  and  Log* 
rithms,  including  Practical  Geometry,  Surveying,  Measuring  of  Tim- 
ber, Cask  and  Malt  Gauging,  Heights,  and  Distances.  By  THOMA* 
KENTISH.  In  one  volume.  i2mo.  *  \  •  «  .  $1.00 

KERL.— The  Assayer's  Manual: 

An  Abridged  Treatise  on  the  Docimastic  Examination  of  Ores,  and 
Furnace  and  other  Artificial  Products.  By  BRUNO  KERL,  Professor 
in  the  Royal  School  of  Mines.  Translated  from  the  German  by 
WILLIAM  T.  BRANNT.  Second  American  edition,  edited  with  Ex- 
tensive Additions  by  F.  LYNWOOD  GARRISON,  Member  of  the 
American  Institute  of  Mining  Engineers,  etc.  Illustrated  by  87  en- 
gravings. 8vo.  (Third  Edition  in  preparation. ) 

KICK. — Flour  Manufacture . 

A  Treatise  on  Milling  Science  and  Practice.  By  FREDERICK  KICK 
Imperial  Regierungsrath,  Professor  of  Mechanical  Technology  in  tht 
imperial  German  Polytechnic  Institute,  Prague.  Translated  from 
the  second  enlarged  and  revised  edition  with  supplement  by  H.  H. 
P.  POWLES,  Assoc.  Memb.  Institution  of  Civil  Engineers.  Illustrated 
with  28  Plates,  and  167  Wood-cuts.  367  pages.  8vo.  .  #10.00 

KINGZETT.— The  History,  Products,  and   Processes  of  the 

Alkali  Trade : 

including  the  most  Recent  Improvements.  By  CHARLES  THOMAS 
KivnzETT.  Consulting  Chemist.  With  23  illustrations.  8vo.  $2.50 

KIRK.— The  Cupola  Furnace : 

A  Practical  Treatise  on  the  Construction  and  Management  of  Foundry 
Cupolas.  By  EDWARD  KIRK,  Practical  Moulder  and  Melter,  Con- 
sulting Expert  in  Melting.  Illustrated  by  78  engravings.  Second 
Edition,  revised  and  enlarged.  450  pages.  8vo.  1903.  $3-5° 

LANDRIN.— A  Treatise  on  Steel: 

Comprising  its  Theory,  Metallurgy,  Properties,  Practical  Working, 
and  Use.  By  M.  H.  C.  LANDRIN,  JR.  From  the  French,  by  A.  A. 
FESQUET.  i2mo .  #2.50 

LANGBEIN.— A   Complete  Treatise  on  the  Electro-Deposi. 

tion  of  Metals : 

.  Comprising  Electro-Plating  and  Galvanoplastic  Operations,  the  De- 
position of  Metals  by  the  Contact  and  Immersion  Processes,  the  Color- 
ing of  Metals,  the  Methods  of  Grinding  and  Polishing,  as  well  as 
Descriptions  of  the  Electric  Elements.  Dynamo-Electric  Machines, 
Thermo-Piles  and  of  the  Materials  and  Processes  used  in  Every  De- 

*  partment  of  the  Art.  From  the  German  of  DR.  GEORGE  LANGBEIN. 
with  additions  by  WM.  T.  BRANNT.  Fifth  Edition,  thoroughly  revised 
and  much  enlarged.  170  Engravings.  694  pages  8vo.  1905.  $4.00 

LARDNER.— The  Steam-Engine : 

For  the  Use  of  Beginners.     Illustrated.     I2mo.    ...       .60 

LEHNER.— The  Manufacture  of  Ink: 

Comprising  the  Raw  Materials,  and  the  Preparation  e>f  Waiting, 
Copying  and  Hektograph  Inks,  Safety  Inks,  Ink  Extracts  and  Pow- 
ders, etc.  Translated  from  the  German  of  SlGMUND  LEHNER,  with 
additions  by  WILLIAM  T.  BRANNT.  Illustrated.  I2mo. 


HENRY  CAREY    BAIRD   &  CO.'S   CATALOGUE.        17 

LARKIN. — The  Practical  Brass  and  Iron  Founder's  Guide  t 
A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals  and 
their  Alloys,  etc.;  to  wnich  are  added  Recent  Improvements  in  the 
Manufacture  of  Iron,  Steel  by  the  Bessemer  Process,  etc.,  etc.  Bj 
JAMES  LARKIN,  late  Conductor  of  the  Brass  Foundry  Department  it 
Reany,  Neafie  &  Co.'s  Penn  Works,  Philadelphia.  New  editioi^ 
revised,  with  extensive  additions.  414  pages.  I2ino.  .  $2.50 

LEROUX. — A    Practical     Treatise    on    the    Manufacture    of 

Worsteds  and  Carded  Yarns  : 

Comprising  Practical  Mechanics,  with  Rules  and  Calculations  applied 
to  Spinning;  Sorting,  Cleaning,  and  Scouring  Wools;  the  English 
and  French  Methods  of  Combing,  Drawing,  and  Spinning  Worsteds, 
and  Manufacturing  Carded  Yarns.  Translated  from  the  French  of 
CHARLES  LEROUX,  Mechanical  Engineer  and  Superintendent  of  a 
Spinning-Mill,  by  HORATIO  PAINE,  M.  D.,  and  A.  A.  FESQUET, 
Chemist  and  Engineer.  Illustrated  by  twelve  large  Plates.  To  which 
is  added  an  Appendix,  containing  Extracts  from  the  Reports  of  thf 
International  Jury,  and  of  the  Artisans  selected  by  the  Commute* 
appointed  by  the  Council  of  the  Society  of  Arts,  London,  on  Woole« 
and  Worsted  Machinery  and  Fabrics,  as  exhibited  in  the  Paris  Uni- 
versal Exposition,  1867.  8vo.  $5.00 

UEFFEL. — The  Construction  of  Mill-Dams  : 
Comprising  also  the  Building  of  Race  and   Reservoir  Embankments 
And   Head-Gates,  the   Measurement  of  Streams,  Gauging  of  Watei 
Supply,  etc.     By  JAMES  LEFFEL  &  Co.    Illustrated  by  58  engravings. 
8vo (Scarce.) 

LESLIE. — Complete  Cookery: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss  LESLIE. 
Sixtieth  thousand.  Thoroughly  revised,  with  the  addition  of  New 
Receipts.  I2mo.  ...  .  $1.50 

LE  VAN. — The  Steam  Engine  and  the  Indicator : 

Their  Origin  and  Progressive  Development ;  including  the  Most 
Recent  Examples  of  Sieam  and  Gas  Motors,  together  with  the  Indi- 
cator, its  Principles,  its  Utility,  and  its  Application.  By  WILLIAM 
BARNET  LE  VAN.  Illustrated  by  205  Engravings,  chiefly  of  Indi- 
cator-Cards. 469  pp.  8vo.  ......  $2.00 

LIEBER.— Assayer's  Guide  ;  ^ 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for  the 
Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the  Ores  of  all 
tfr  principal  Metals,  of  Gold  and  Silver  Coins  and  Alloys,  and  of 
Coal,  etc.  By  OSCAR  M.  LIEBER.  Revised.  283  pp.  121110.  £1.50* 

Lockwood's  Dictionary  of  Terms  : 

Used  in  the  Practice  of  Mechanical  Engineering,  embracing  those 
Current  in  the  Drawing  Office,  Pattern  Shop,  Foundry,  Fitting,  Turn- 
jng,  Smith's  and  Boiler  Shops,  etc.,  etc.,  comprising  upwards  of  Six 
Thousand  Definitions.  Edited  by  a  Foreman  Pattern  Maker,  author 
of  "  Patter*  Making.".  417  pp.  I2mo.  .  .  . 


18         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE 

LUKIN.— The  Lathe  and  Its  Uses : 

Or  Instruction  in  the  Art  of  Turning  Wood  and  Metal.  Including 
a  Description  of  the  Most  Modern  Appliances  for  the  Ornamentation 
of  Plane  and  Curved  Surfaces,  an  Entirely  Novt-1  Form  of  Lathe 
for  Eccentric  and  Rose-Engine  Turning;  A  Lathe  and  Planing 
Machine  Combined;  and  Other  Valuable  Matter  Relating  to  the 
Art.  Illustrated  by  462  engravings.  Seventh  edition.  315  pages. 
8vo $4.25 

MAIN  and  BROWN. — Questions  on  Subjects  Connected  with 

the  Marine  Steam-Engine : 

And  Examination  Papers;  with  Hints  for  their  Solution.  By 
THOMAS  J.  MAIN,  Professor  of  Mathematics,  Royal  "Waval  College, 
and  THOMAS  BROWN,  Chief  Engineer,  R.  N.  I2mo.,  cloth  .  $1.00 

MAIN  and  BROWN. — The  Indicator  and  Dynamometer: 
With  their  Practical  Applications  to  the  Steam-Engine.     By  THOMAS 
J.   MAIN,   M.  A.  F.  R.,   Ass't    S.    Professor   Royal   Naval   College, 
Portsmouth,  and  THOMAS  BROWN,  Assoc.  Inst.  C.  E.,  Chief  Engineer 
R.  N.,  attached  to  ihe  R.  N.  College.     Illustrated.     8vo.  . 

MAIN  and  BROWN.— The  Marine  Steam-Engine. 
By  THOMAS  J.  MAIN,  F.  R.  Ass't  S.  Mathematical  Professor  at  the 
Royal    Naval    College,    Portsmouth,  and    THOMAS    BROWN,   Assoc. 
Inst.  C.  E.,  Chief  Engineer  R.  N.     Attached  to  the  Royal  Naval 
College.     With  numerous  illustrations.     8vo. 

MAKINS.— A  Manual  of  Metallurgy: 

By  GEORGE  HOGARTH  MAKINS.  100  engravings.  Second  edition 
rewritten  and  much  enlarged.  I2mo.,  592  pages  .  •  . 

MARTIN.— Screw-Cutting  Tables,  for  the  Use  of  Mechanic*) 

Engineers  : 

Showing  the  Proper  Arrangement  of  Wheels  for  Cutting  the  Threads 
of  Screws  of  any  Required  Pitch ;  with  a  Table  for  Making  the  Uni- 
versal Gas- Pipe  Thread  and  Taps.  By  W.  A.  MARTIN,  Engineer. 
8vo .50 

MICHELL.— Mine  Drainage: 

Being  a  Complete  and  Practical  Treatise  on  Direct-Acting  Under 
grcund  Steam  Pumping  Machinery.  With  a  Description  of  a  large 
number  of  the  best  known  Engines,  their  General  Utility  and  ih« 
Special  Sphere  of  their  Action,  the  Mode  of  their  Application,  and 
their  Merits  compared  with  other  Pumping  Machinery.  By  STEPHEN 
MlCHELL.  Illustrated  by  247  engravings.  8vo.,  369  pages.  $12  50 

MOLESWORTH.— Pocket-Book   of    Useful    Formulae   and 
Memoranda  for  Civil  and  Mechanical  Engineers. 
By  GUILFORD  L.  MOLESWORTH,  Member  of  the  Institution  of  Civil 
Engineers,  Chief  Resident  Engineer  of  the  Ceylon  Railway.     Full- 
bound  in  Pocket-book  form 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE* 


HOORE.— The  Universal  Assistant  and  the  Complete  Mi 
chanic : 

Containing  over  one  million  Industrial  Facts,  Calculations,  Receipt*, 
Processes,  Trades  Secrets,  Rules,  Business  Forms,  Legal  Items,  Etc., 
in  every  occupation,  from  the  Household  to  the  Manufactory.  Bj 
R.  MOORE.  Illustrated  by  500  Engravings.  I2mo.  .  $2.50 

MORRIS. — Easy  Rules  for  the  Measurement  of  Earthworks: 
By  means  of  the  Prismoidal  Formula.  Illustrated  with  Numerour 
Wood-Cuts,  Problems,  and  Examples,  and  concluded  by  an  Exten- 
sive Table  for  finding  the  Solidity  in  cubic  yards  from  Mean  Areas, 
The  whole  being  adapted  for  convenient  use  by  Engineers,  Surveyor^ 
Contractors,  and  others  needing  Correct  Measurements  of  Earthwork 
By  ELWOOD  MORRIS,  C.  E.  8vo $1.54 

MAUCHLINE.— The  Mine  Foreman's  Hand-Book 
Of  Practical  and  Theoretical  Information  on  the  Opening,  Venti- 
lating, and  Working  of  Collieries.  Questions  and  Answers  on  Prac- 
tical  and  Theoretical  Coal  Mining.  Designed  to  Assist  Students  and 
Others  in  Passing  Examinations  for  Mine  Foremanships.  By 
ROBERT  MAUCHLINE.  3d  Edition.  Thoroughly  Revised  and  En- 
larged by  F.  ERNEST  BRACKETT.  134  engravings,  8vo.  378  pages. 
(1905) £3.75 

NAPIER.— A  System  of  Chemistry  Applied  to  Dyeing. 
By  JAMES  NAPIER,  F.  C.  S.  A  New  and  Thoroughly  Revised  Edi- 
tion. Completely  brought  up  to  the  present  state  of  the  Science, 
including  the  Chemistry  of  Coal  Tar 'Colors,  by  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  Appendix  o.i  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867.  Illus 
trated.  8vo.  422  pages $3.00 

NEVILLE.— Hydraulic  Tables,  Coefficients,  and  Formulae,  foi 
finding  the  Discharge  of  Water  from  Orifices,  Notches 
Weirs,  Pipes,  and  Rivers : 

Third  Edition,  with  Additions,  consisting  of  New  Formulae  for  the 
)ischarge  from  Tidal  and  Flood  Sluices  and  Siphons;  general  infor 
nation  on  Rainfall,  Catchment-Basins,  Drainage,  Sewerage,  Wa.ei 
SupDly  for  Towns  and  Mill  Power  Bv  JOHN  NF.VTTT.K.  C.  E.  M  R 
I,  A. ;  Fellow  of  the  Royal  Geological  Society  of  Ireland.  Thicl 
12mo #5.50 

NEWBERY.— Gleanings     from     Ornamental     Art    of     everj 

style : 

Drawn  from  Examples  in  the  British,  South  Kensington,  Indian, 
Crystal  Palace,  and  other  Museums,  the  Exhibitions  of  1851  and 
1862,  and  the  best  English  and  Foreign  works.  In  a  series  of  ioa 
exquisitely  drawn  Plates,  containing  many  hundred  examples.  Bjf 
ROBERT  NEWBERY.  410. (Scarce.^ 

NICHOLLS.  -The  Theoretical  and  Practical  Boiler-Maker  an* 

Engineer's  Reference  Book: 

Containing  a  variety  of  Useful  Information  for  Employers  of  Labor. 
Foremen  a*%d  Working  Boiler-Makers.  Irow,  Copper,  and  Tinsmiths 


so        HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 


Draughtsmen,  Engineers,  the  General  Steam-using  Public,  and  for  thi 
Use  of  Science  Schools  and  Classes.  By  SAMUEL  NiCHOLLS.  Illus* 
trated  by  sixteen  plaies,  I2mo. $2,50 

NICHOLSON.— A  Manual  of  the  Art  of  Bookbinding : 
Containing  full  instructions  in  the  different  Branches  of  Forwarding, 
Gilding,  and  Finishing.     Also,  the  Art  of  Marbling  Book-edges  and 
Paper.     By  JAMES  B.  NICHOLSON.     Illustrated.  I2mo.,  cloth     $2.2$, 

NICOLLS.— The  Railway  Builder: 

A  Hand-Book  for  Estimating  the  Probable  Cost  of  American  Rail- 
way  Construction  and  Equipment.  By  WILLIAM  J.  NICOLLS,  Civil 
Engineer.  Illustrated,  full  bound,  pocket-book  form  .  $2.00 

NORMANDY.— The  Commercial  Handbook  of  Chemical  An. 

alysis : 

Or  Practical  Instructions  for  the  Determination  of  the  Intrinsic  01 
Commercial  Value  of  Substances  used  in  Manufactures,  in  Trades, 
and  in  the  Arts.  By  A.  NORMANDY.  New  Edition,  Enlarged,  and 
to  a  great  extent  rewritten.  By  HENRY  M.  NOAD,  Ph.D.,  F.R.S., 
thick  I2mo Scarce 

NORRIS.— A  Handbook  for  Locomotive   Engineers  and  Ma- 
chinists : 

Comprising  the  Proportions  and  Calculations  for  Constructing  Loco- 
motives;  Manner  of  Setting  Valves;  Tables  of  Squares,  Cubes,  Areas, 
etc.,  etc.  By  SEPTIMUS  NORRIS,  M.  E.  New  edition.  Illustrated, 
I2mo $1.50 

NYSTROM. — A  New  Treatise  on  Elements  of  Mechanics : 
Establishing  Strict  Precision  in  the   Meaning  of  Dynamical  Terms  j 
accompanied  with  an  Appendix  on  Duodenal  Arithmetic  and   Me 
trology.     By  JOHN  W.  NYSTROM,  C.  E.     Illustrated.     8vo. 

NYSTROM. — On  Technological  Education  and  the  Construe* 

tion  of  Ships  and  Screw  Propellers : 

For  Naval  and  Marine  Engineers.  By  JOHN  W.  NYSTROM,  lat«, 
Acting  Chief  Engineer,  U.  S.  N.  Second  edition,  revised,  with  addi 
tional  matter.  Illustrated  by  seven  engravings,  izmo.  .  $1.2$ 

O'NEILL. — A  Dictionary  of  Dyeing  and  Calico  Printing: 

Containing  a  brief  account  of  all  fhe  Substances  and  Processes  it, 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  ;  with  Practical 
Receipts  and  Scientific  Information.  By  CHARLES  O'NEILL,  Analy- 
tical Chemist.  To  which  is  added  an  Essay  on  Coal  Tar  Colors  and 
their  application  to  Dyeing  and  Calico  Printing.  By  A.  A.  FESQUETJ 
Chemist  and  Engineer.  With  an  appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867-  8vo., 
491  pages  .  .  .  *  .  .  .  .  $3.00 

ORTON. — Underground  Treasures'. 

How  and  Where  to  Find  Them.  A  Key  for  the  Ready  Determination 
til  all  the  Useful  Minerals  within  the  United  States.  By  JAMES 
ORTON,  A.M.,  Late  Professor  of  Natural  History  in  Vassar  College, 
N.  Y.;  author  of  the  "  Andes  and  the  Amazon,"  etc.  A  New  Edi- 
tion, with  An  Appendix  on  Ore  Deposits  and  Testing  Minerals  (1901). 
Illustrated ,  $1.50 


HENRY    CAREY    BAIRD   &   CO.'S   CATALOGUE.        21 


OSBORN. — The  Prospector's  Field  Book  and  Guide. 

In  the  Search  For  and  the  Easy  Determination  of  Ores  and  Other 
Useful  Minerals.  By  Prof.  11.  S.  OSBORN,  LL.  D.  Illustrated  by  66 
Engravings.  Sixth  Edition.  Revised  and  Enlarged.  360  pages, 

I2mo.      (Dec.,  1903) $1.50 

OSBORN — A  Practical  Manual  of  Minerals,  Mines  and  Mm 

ing : 

Comprising  the  Physical  Properties,  Geologic  Positions,  Local  Occur- 
rence and  Associations  of  the  Useful  Minerals;  their  Methods  of 
Chemical  Analysis  and  Assay  ;  together  with  Various  Systems  of  Ex- 
cavating and  Timbering,  Brick  and  Masonry  Work,  during  Driving, 
Lining,  Bracing  and  other  Operations,  etc.  By  Prof.  II.  S.  OSBORN, 
LL.  D.,  Author  of  "  The  Prospector's  Field-Book  and  Guide."  171 
engravings.  Second  Edition,  revised.  8vo.  ...  £4*50 
3VERMAN.— The  Manufacture  of  Steel : 

Containing  the  Practice  and  Principles  of  Working  and  Making  Steel. 
A  Handbook  for  Blacksmiths  and  Workers,  in  Steel  and  Iron,  Wagon 
Makers,  Die  Sinkers,  Cutlers,  and  Manufacturers  of  Files  and  Hard- 
ware,   of  Sl»>el   an<J    Iron,  and  for   Men   of  Science  and  Art.     By 
FREDERICK  OVERMAN,  Mining  Engineer,  Author  of  the  "  Manu- 
facture of  lion,"  etc.     A  new,  enlarged,  and  revised  Edition.     By 
A.  A.  FESQI/£T,  Chemist  and  Engineer.     I2mo.         .         .         $1.50 
OVERMAN.— The  Moulder's  and  Founder's  Pocket  Guide  : 
A  Treatise  on  Moulding  and  Founding  in  Green-sand,  Dry-sand,  Loam, 
and  Cement;  the  Moulding  of  Machine  Frames,  Mill-gear,  Hollow, 
ware,  Ornaments,  Trinkets,  Bells,  and  Statues;  Description  of  Moulds 
for  Iron,  Brcnze,  Brass,  and  other  Metals;   Plaster  of  Paris,  Sulphur, 
Wax,  etc. ;  the  Construction  of  Melting  Furnaces,  the  Melting  and 
Founding  of  Metals  ;  the  Composition  of  Alloys  and  their  Nature, 
etc.,  etc.     By   FREDERICK  OVERMAN,  M.  E.     A  new  Edition,  to 
which  is  added  a  Supplement  on  Statuary  and  Ornamental  Moulding, 
Ordnance,  Malleable  Iron  Castings,  etc.     By  A.  A.  FESQUET,  Chem- 
ist and  Engineer.     Illustrated  by  44  engravings.     I2mo.    .        $2.OQ 
PAINTER,  GILDER,  AND  VARNISHER'S  COMPANION. 
Comprising  the  Manufacture  and  Test  of  Pigments,  the  Arts  of  Paint- 
ing, Graining,  Marbling,  Staining,  Sign- writing,  Varnishing,  Glass- 
s-taining,  and   Gilding  on  Glass;   together  with  Coach  Painting  and 
Varnishing,   and  the    Principles   of  the  Harmony  and  Contrast  of 
Colors.     Twenty-seventh  Edition.     Revised,  Enlarged,  and  in  great 
part  Rewritten.     By  WILLIAM  T.  BRANNT,  Editor  of  "  Varnishes, 
Lacquers,  Printing  Inks  and  Sealing  Waxes."     Illustrated.     395  pp. 
I2mo.       .         .         .         ,         .         .         .     "    .         .         .         $i  50 
PALLETT.— The  Miller's,  Millwright's, and  Engineer's  Guide. 
By  HENRY  PALLETT.     Illustrated.     i2mo.       .        .        .        $2.00 


22         riENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

PERCY.— The  Manufacture  of  Russian  Sheet-Iron. 

By  JOHN  PERCY,  M.  D.,  F.  R.  S.     Paper.      .        .        .        25  cts. 
PERKINS.— Gas  and  Ventilation: 

Practical  Treatise  on  Gas  and  Ventilation.    Illustrated.    I2mo.    $1.25 
PERKINS  AND  STOWE.— A  New  Guide  to  the  Sheet-iron 

and  Boiler  Plate  Roller : 

Containing  a  Series  of  Tables  showing  the  Weight  of  Slabs  and  Piles 
to  Produce  Boiler  Plates,  and  of  ihe  Weight  of  Piles  and  the  Sizes  of 
Bars  to  produce  Sheet-iron ;  the  Thickness  of  the  Bar  Gauge 
in  decimals ;  the  Weight  per  foot,  and  the  Thickness  on  the  Bar  or 
Wire  Gauge  of  the  fractional  parts  of  an  inch;  the  Weight  per 
sheet,  and  the  Thickness  on  the  Wire  Gauge  of  Sheet-iron  of  various 
dimensions  to  weigh  112  Ibs.  per  bundle;  and  the  conversion  of 
Short  Weight  into  Long  Weight,  and  Long  Weight  into  Short. 

$1.50 

POSSELT. — Recent  Improvements  in  Textile  Machinery  Re- 
lating to  Weaving: 

Giving  the  Most  Modern  Points  on  the  Construction  of  all,,  Kinds 
of  Looms,  Warpers,  Beamers,  Slashers,  Winders,  Spoolers,  Reeds, 
Temples,  Shuttles,  Bobbins,  Heddles,  Heddle  Frames,  Pickers, 
Jacquards,  Card  Stampers,  etc.,  etc.  600  illus.  .  .  $3  oo 
POSSELT.— Technology  of  Textile  Design: 

The  Most  Complete  Treatise  on  the  Construction  and  Application 
of  Weaves  for  all  Textile  Fabrics  and  the  Analysis  of  Cloth.     By  E. 
A.  Posselt.     1,500  illustrations.     410.        ....         $5-OO 
POSSELT. — Textile  Calculations: 

A  Guide  to  Calculations   Relating  to  the  Manufacture  of  all  Kinds 
of  Yarns  and  Fabrics,  the  Analysis  of  Cloth,  Speed,  Power  and  Belt 
Calculations.     By  E.  A.  POSSELT.     Illustrated.     410.        .        $2.00 
REGNAULT. — Elements  of  Chemistry: 

By  M.  V.  REGNAULT.  Translated  from  the  French  by  T.  FORREST 
BETTON,  M.  D.,  and  edited,  with  Notes,  by  JAMES  C.  BOOTH,  Melter 
and  Refiner  U.  S.  Mint,  and  WILLIAM  L.  FABER,  Metallurgist  and 
Mining  Engineer.  Illustrated  by  nearly  700  wood-engravings.  Com- 
prising nearly  1,500  pages.  In  two  volumes,  8vo.,  cloth  .  $6.00 
RICHARDS.— Aluminium : 

Its  History,  Occurrence,  Properties,  Metallurgy  and  Applications, 
including  its  Alloys.  By  JOSEPH  W.  RICHARDS,  A.  C.,  Chemist  and 
Practical  Metallurgist,  Member  of  the  Deutsche  Chemische  Gesell- 
schaft.  Illust.  Third  edition,  enlarged  and  revised  (1895)  .  $6.00 
RIFFAULT,  VERGNAUD,  and  TOUSSAI.NT.— A  Practical 

Treatise  on  the  Manufacture  of  Colors  for  Painting  : 
Comprising  the  Origin,  Definition,  and  Classification  of  Colors;  the 
Treatment  of  the  Raw  Materials ;  the  best  Formulae  and  the  Newest 
Processes  for  the  Preparation  of  every  description  of  Pigment,  and 
the  Necessary  Apparatus  and  Directions  for  its  Use;  Dryers;  the 
Testing.  Application,  and  Qualities  of  Paints,  etc.,  etc.  By  MM. 
PIFFAULT,  VERGNAUD,  and  TOUSSAIKT.  Revised  and  Edited  by  M, 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          23 


F.  MALEPEYRE.    Translated  from  the  French,  by  A.  A. 

Chemist  and  Engineer.     Illustrated  by  Eighty  engravings.     In  one 

vol.,  8vo.,  659  pages          .....         •  $5'°° 

ROPER.  —  Catechism  for  Steam  Engineers  and  Electricians: 
Including   the    Construction  and  Management   of   Steam    Engines, 
Steam  Boilers  and  Electric  Plants.     By  STEPHEN  ROPER.     Twenty- 
first  edition,  rewritten  and   greatly  enlarged  by  E.  R.  KELLLR  and 
C.  W.  PIKE.     365  pages.     Illustrations.      i8mo.,  tucks,  gilt.     $2.00 

ROPER.—  Engineer's  Handy  Book: 

Containing  Facts,  Formulae,  Tables  and  Questions  on  Power,  its 
Generation,  Transmission  and  Measurement;  Heat,  Fuel,  and  Steam; 
The  Steam  Boiler  and  Accessories  ;  Steam  Engines  and  their  Parts  ; 
Steam  Engine  Indicator;  Gas  and  Gasoline  Engines;  Materials; 
their  Properties  and  Strength  ;  Together  witli  a  Discussion  of  the  Fun- 
damental Experiments  in  Electricity,  and  an  Explanation  of  Dynamos, 
Motors,  Batteries,  etc.,  and  Rules  for  Calculating  Sizes  of  Wires.  By 
STEPHEN  ROPER.  I5th  edition.  Revised  and  enlarged  by  E.  R. 
KELLER,  M.  E.  and  C.  W.  PIKE,  B.  S.  (1899),  with  numerous  illus- 
trations. Pocket-book  form.  Leather  .....  $3.50 

ROPER.  —  Hand-Book  of  Land  and  Marine  Engines  : 
Including  the  Modelling,  Construction,   Running,  and  Management 
of  Lane1  and  Marine  Engines  and  Boilers.     With  illustrations.     By 
STEPHEN  ROPER,  Engineer.    Sixth  edition.     I2mo.,tx'cks,  gilt  edge. 

£3.50 
ROPER.—  Hand-Book  of  the  Locomotive  : 

Including  the  Construction  of  Engines  and  Boilers,  and  the  Construc- 
tion,   Management,    and    Running   of  Locomotives.     By    STEPHEN 
ROPER.     Eleventh  edition.     i8mo.,  tucks,  gilt  edge  .         #2.5(1 

ROPER.  —  Hand-Book  of  Modern  Steam  Fire-Engines. 
With  illustrations.     By  STEPHEN  ROPER,  Engineer.     Fourth  edition, 
I2mo.,  tucks,  gilt  edge       .         ......         $3-50 

ROPER.  —  Questions  and  Answers  for  Engineers. 

This  little   book  contains  all  the  .Questions  that  Engineers  will  be 
asked  when  undergoing  an  Examination  for  the  purpose  of  procuring 
Licenses,  and  they  are  so  plain  that  any  Engineer  or  Fireman  of  or- 
dinary intelligence  may  commit  them  to  memory  in  a  short  time.     By 
STEPHEN  ROPER,  Engineer.     Third  edition       .         .         .         £2.00 
ROPER.—  Use  and  Abuse  of  the  Steam  Boiler. 
By  STEPHEN   ROPER,  Engineer.     Eighth  edition,  with  illustrations. 
l8mo.,  tucks,  gilt  edge       .......         J>2.OO 

ROSE.  —  The  Complete  Practical  Machinist  : 

Embracing  Lathe  Work,  Vise  Work,  Drills  and  Drilling,  Taps  and 
Dies,  Hardening  and  Tempering,  the  Making  and  Use  of  Tools 
Tool  Grinding,  Marking  out  Work,  Machine  Tools,  etc.  By  JOSHUA 
ROSE.  395  Engravings.  Nineteenth  Edition,  greatly  Enlarged  with 
New  and  Valuable  Matter.  I2mo.,  504  pages.  .  .  $2.50 
ROSE.  —  Mechanical  Drawing  Self-Taught  : 

Comprising  Instructions  in  the  Selection  and  Preparation  of  Drawing 
Tnstruments,  Elementary  Instruction  in  Practical  Mechanical  Draw- 


24         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

ing,  together  with  Examples  in  Simple  Geometry  and  Elementary 
Mechanism,  including  Screw  Threads,  Gear  Wheels,  Mechanical 
Motions,  Engines  and  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  330  engravings.  8vo  ,313  pages  .  .  .  .  $4.00 

ROSE. — The  Slide- Valve  Practically  Explained: 

Embracing  simple  and  complete  Practical  Demonstrations  of  th, 
operation  of  each  element  in  a  Slide-valve  Movement,  and  illustrat- 
ing the  effects  of  Variations  in  their  Proportions  by  examples  care, 
fully  selected  from  the  most  recent  and  successful  practice.  By 
JOSHUA  ROSE,  M.  E.  Illustrated  by  35  engravings  •  .  $i.oo 

ROSS. — The  Blowpipe  in  Chemistry,  Mineralogy  and  Geology: 
Containing  all  Known  Methods  of  Anhydrous  Analysis,  many  Work- 
ing Examples,  and  Instructions  for  Making  Apparatus.  By  LIEUT.- 
COLONEL  W.  A.  Ross,  R.  A.,  F.  G.  S.  With  120  Illustrations. 
I2mo.  .  .  . '  ,  '  /. $2.0O 

SHAW.— Civil  Architecture : 

Being  a  Complete  Theoretical  and  Practical  System  of  Building,  con- 
taining  the  Fundamental  Principles  of  the  Art.  By  EDWARD  SHAW, 
Architect.  To  which  is  added  a  Treatise  on  Gothic  Architecture,  etc. 
By  THOMAS  W.  SILI.OWAY  and  GEORGE  M.  HARDING,  Architects. 
The  whole  illustrated  by  102  quarto  plates  finely  engraved  on  copper. 
Eleventh  edition.  4to.  .......  #6.00 

SHUNK. — A  Practical  Treatise  on  Railway  Curves  and  Loca- 
tion, for  Young  Engineers. 

By  W.  F.  SHUNK,  C.  E.     I2mo.    Full  bound  pocket-book  form  $2.00 

SLATER.— The  Manual  of  Colors  and  Dye  Wares. 
By  J.  W.  SLATER.     I2mo #3.00 

SLOAN. — American  Houses: 

A  variety  of  Original  Designs  for  Rural  Buildings.  Illustrated  by 
26  colored  engravings,  with  descriptive  references.  By  SAMUEL 
SLOAN,  Architect.  8vo.  .  .  .  *  .  .  .75 

SLOAN.— Homestead  Architecture: 

Contain!^  Forty  Designs  for  Villas,  Cottages,  and  Farm-houses,  witb 
Essays  on  Style,  Construction,  Landscape  Gardening,  Furniture,  etc., 
etc.  Illustrated  by  upwards  of  200  engravings.  By  SAMUEL  SLOAN, 
Architect.  8vo.  .  ..-.-,,  .  .  .  .  $2  50 

SLOANE. — HoiT>e  Experiments  in  Science. 
By  T.  O'CONOR  SLCANE,  E.  M.,  A.  M.,  Fh.  O.     Illustrated  by  91 
engravings.     I2mo.  .         .         .         .         .         .'  -   .        $l.oo 

SM EATON.— Builder's  Pockti -Companion : 

Containing  the  Elements  of  Building,  Surveying,  and  Architecture; 
with  Practical  Rules  and  Instructions  connected  with  the  subject. 
By  A.  C.  SMEATON,  Civil  Engineer,  etc.  I2mo. 

SMITH. — A  Manual  of  Political  Economy. 
By  E.  PESHINE  SMITH.    A  New  Edition,  to  which  is  added  a  full 
Index.     I2mo,          ,  .        ...         .        $l  25 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          25 

SMITH. — Parks  and  Pleasure  -  Grounds : 

Or  Practical  Notes  on  Country  Residences,  Villas,  Public  Parks,  And 
Gardens.  By  CHARLES  H.  J.  SMITH,  Landscape  Gardener  and. 
Garden  Architect,  etc.,  etc.  I2mo.  ....  $2.oa. 

SMITH.— The  Dyer's  Instructor: 

Comprising  Practical  Instructions  in  the  Art  of  Dyeing  Silk,  Cotton^ 
Woo!,  and  Worsted,  and  Woolen  Goods;  containing  nearly  8oO" 
Receipts.  To  which  is  added  a  Treatise  on  the  Art  of  Padding;  ancj 
t'ie  Printing  of  Silk  Warps,  Skeins,  and  Handkerchiefs,  and  th«l 
v  irious  Mordants  and  Colors  for  the  different  styles  of  such  work/ 

,    By  DAVID  SMITH,  Pattern  Dyer.     I2mo.  .         .         .        $1.50! 

£  /IYTH.— A  Rudimentary  Treatise  on  Coal  and  Coal-Mining. 
By  WARRINGTON  W.  SMYTH,  M.  A.,  F.  R.  G.,  President  R.  G.  S,i 
of   Cornwall.     Fifth  edition,  revised   and  corrected.     With   numer- 
ous illustrations.      I2mo.  ......         $1.4° 

SNIVELY. — Tables  for  Systematic  Qualitative  Chemical  Anal. 

ysis. 
By  JOHN  H.  SNIVELY,  Phr.  D.     8vo.        ....        $1.00 

SNIVELY.— The  Elements  of  Systematic  Qualitative  chemical 

Analysis  : 

A  Hand-book  for  Beginners.    By  JOHN  H.  SNIVELY,  Phr.  D.    l6mo. 

^2.00 

STOKES.— The  Cabinet  Maker  and  Upholsterer's  Companion: 
Comprising  the  Art  of  Drawing,  as   applicable  to   Cabinet   Work; 
Veneering,  Inlaying,  and   Buhl- Work;  the  Art  of  Dyeing  and  Stain 
ing  Wood,  Ivory,  Bone,  Tortoise-Shell,  etc.     Directions  for  Lacker- 
ing, Japanning,   and    Varnishing;    to   make  French    Polish,  Glues, 
Cements,  and  Compos       «is;  with  numerous  Receipts,  useful  to  work 
men  generally.      BV       STOKES.    -Illustrated.     A  New  Edition,  with 
an  Appendix  upor      .ench  Polishing,  Staining,  Imitating,  Varnishing, 
etc.,  etc.    I2mo          ........         $1.25 

STRENGTH  AND  OTHER  PROPERTIES  OF  METALS; 
Reports   of  Experiments  on  the   Strength   and   other  Properties  of 
Metals  for  Cannon.     With  a  Description  of  the  Machines  for  Testing 
Metals,  and  of  the  Classification  of  Cannon  in  service.     By  Officer? 
of  the  Ordnance  Department,  U.  S.  Army.     By  authority  of  the  Secre- 
tary of  War.     Illustrated  by  25  large  steel  plates.    Quarto  .        $5.00 
SULLIVAN. — Protection  to  Native  Industry. 
By  Sir  EDWARD  SULLIVAN,  Baronet,  author  of  "  Ten  Chapters  on 
Social  Reforms."     8vo.     .......         $1.00 

SHERRATT.— The  Elements  of  Hand-Railing: 

Simplified  and  Explained  in  Concise  Problems  that  are  Easily  Under- 
stood. The  whole  illustrated  with  Thirty-eight  Accurate  and  Origi- 
nal Plates,  Founded  on  Geometrical  Principles,  and  Showing  how  to 
Make  Rail  Without  Centre  Joints,  Making  Better  Rail  of  the  Same 
Material,  with  Half  the  Labor,  and  Showing  How  to  Lay  Out  Stairs 
of  all  Kinds.  By  R.  J.  SHERRATT.  Folio.  .  .  .  $2.50 


26        HENRY  CAREY  BAIRu  &  CO.'S  CATALOGUE. 


BYME.—Outlines  of  an  Industrial  Science. 

By  DAVID  SYME.     I2mo.          v        .  'f=u.  -:     .         .         $2.00 

TABLES     SHOWING     THE     WEIGHT     OF     ROUND, 
SQUARE,  AND  FLAT  BAR  IRON,  STEEL,  ETC., 

By  Measurement.     Cloth  ivc  '.  "*   :.  -  -  '-*':~^- * "-'•-•  63 

TH  A  LLNER.— Tool-Steel : 

A  Concise  Handbook  on  Tool-Steel  in  General.  Its  Treatment  in 
the  Operations  of  Forging,  Annealing,  Hardening,  Tempering,  etc., 
and  the  Appliances  Therefor.  By  OTTO  THALLNER,  Manager  in 
Chief  of  the  Tool-Steel  Works,  Bismarck htitte,  Germany.  From  the 
German  by  WILLIAM  T.  BRANNT.  Illustrated  by  69  engravings. 
194  pages.  8vo.  1902.  .  .r  .  .  .  .  $2.00 

TEMPLETON. — The  Practical  Examinator  on  Steam  and  thd 

Steam -Engine: 

With  Instructive  References  relative  thereto,  arranged  for  the  Use  of 
Engineers,  Students,  and  others.  By  WILLIAM  TEMPLETON,  En. 
gineer.  I2mo.  .  .  .  .  •  •  •  .  $1.00 

THAUSING.— The  Theory  and  Practice  of  the  Preparation  of 

Malt  and  the  Fabrication  of  Beer: 

With  especial  reference  to  the  Vienna  Process  of  Brewing.  Elab- 
orated from  personal  experience  by  JULIUS  E.  THAUSING,  Professor 
at  the  School  for  Brewers,  and  at  the  Agricultural  Institute,  Modling, 
near  Vienna.  Translated  from  the  German  by  WiLLIAM  T.  BRANNT, 
Thoroughly  and  elaborately  edited,  with  much  American  matter,  and 
according  to  the  latest  and  most  Scientific  Practice,  by  A.  SCHWARZ 
and  DR.  A.  H.  BAUER.  Illustrated  by  140  Engravings.  8vo.,  815 
pages  .  »  .  .  ,  ...  .  .  $10.00 

THOMPSON. — Political  Economy.     With  Especial  Reference 

to  the  Industrial  History  of  Nations  : 

By  ROBERT  E.  THOMPSON,  M.  A.,  Professor  of  Social  Science  in  the 
University  of  Pennsylvania.  I2mo.  .  .,  .  ,  .  ."..-.  $1.50 

THOMSON.— Freight  Charges  Calculator: 

By  ANDREW  THOMSON,  Freight  Agent.     24mo.        .       ...  .    $1.25 

TURNER'S  (THE)  COMPANION: 

Containing  Instructions  in  Concentric,  Elliptic,  and  Eccentric  Turn- 
ing; also  various  Plates  of  Chucks,  Tools,  and  Instruments;  and 
Directions  for  using  the  Eccentric  Cutter,  Drill,  Vertical  Cutter,  and 
Circular  Rest;  with  Patterns  and  Instructions  for  working  them 
I2mo $I.oo 

TURNING  :   Specimens  of  Fancy  Turning  Executed  on  the 

Hand  or  Foot- Lathe : 

With  Geometric,  Oval,  and  Eccentric  Chucks,  and  Elliptical  Cutting 
Frame.  By  an  Amateur.  Illustrated  by  30  exquisite  Photographs. 
4to.  .  . '•._  ,  ......  (Scarce.) 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          27 

VAILE.— Galvanized- Iron  Cornice-Worker's  Manual: 

Containing  Instructions  in  Laying  out  the  Different  Mitres,  and 
Making  Patterns  for  all  kinds  of  Plain  and  Circular  Work.  Also, 
Tables  of  Weights,  Areas  and  Circumferences  of  Circles,  and  other 
Matter  calculated  to  Benefit  the  Trade.  By  CHARLES  A.  VAILE. 
Illustrated  by  twenty-one  plates.  4to.  .  ,  .  .(Scarce.) 

VILLE. — On  Artificial  Manures  : 

Their  Chemical  Selection  and  Scientific  Application  to  Agriculture. 
A  series  of  Lectures  given  at  the  Experimental  Farm  at  Vincennes, 
during  1867  and  1874-75.  By  M.  GEORGES  VILLE.  Translated  and 
Edited  by  WILLIAM  CROOKES,  F.  R.  S.  Illustrated  by  thirty-one 

engravings.    8vo.,  450  pages $6.00 

VILLE. — The  School  of  Chemical  Manures  : 
Or,  Elementary  Principles  in  the  Use  of  Fertilizing  Agents.     From 
the  French  of  M.  GEO.  VILLE,  by  A.  A.  FESQUET,  Chemist  and  En- 
gineer.    With  Illustrations.     I2mo.  ....         $1.25 
VOGDES. — The  Architect's  and  Builder's  Pocket-Companion 

and  Price-Book : 

Consisting  of  a  Shoii  but  Comprehensive  Epitome  of  Decimals,  Duo- 
decimals, Geometry  and  Mensuration ;  with  Tables  of  United  States 
Measures,  Sizes,  Weights,  Strengths,  etc.,  of  Iron,  Wood,  Stone, 
TJrick,  Cement  and  Concretes,  Quantities  of  Materials  in  given  Sizes 
and  Dimensions  of  Wood,  Brick  and  Stone;  and  full  and  complete 
Bills  of  Prices  for  Carpenter's  Work  and  Painting ;  also,  Rules  for 
Computing  and  Valuing  Brick  and  Brick  Wrork,  Stone  Work,  Paint- 
ing, Plastering,  with  a  Vocabulary  of  Technical  Terms,  etc.  By 
FRANK  W.  VOGDES,  Architect,  Indianapolis,  Ind.  Enlarged,  revised, 
and  corrected.  In  one  volume,  368  pages,  full-bound,  pocket-book 

form,  gilt  edges $2.00 

Cloth         .  1.50 

VAN  CLEVE. — The  English  and  American  Mechanic: 
Comprising  a  Collection  of  Over  Three  Thousand  Receipts,  Rules, 
and  Tables,  designed  for  the  Use  of  every  Mechanic  and  Manufac- 
turer. By  B.  FRANK  VAN  CLEVE.  Illustrated.  500  pp.  i2mo.  $2.00 
VAN  DER  BURG.— School  of  Painting  for  the  Imitation  of 

Woods  and  Marbles: 

A  Complete,  Practical  Treatise  on  the  Art  and  Craft  of  Graining  and 
Marbling  with  the  Tools  and  Appliances.  ^6  plates.  Folio,  12x20 

inches •         -         •         #10.00 

WAHNSCHAFFE. — A  Guide  to  the  Scientific  Examination 

of  Soils: 

Comprising  Select  Methods  of  Mechanical  and  Chemical  A  lalystf 
and  Physical  Investigation.  Translated  from  the  German  of  Dr.  F, 
WAHNSCHAFFE.  With  additions  by  WILLIAM  T.  BRANNT.  Illus- 
trated by  25  engravings.  121110.  177  pages  .  .  .  $1.50 
fVALTON.— Coal-Mining  Described  and  Illustrated: 
By  THOMAS  H.  WALTON,  Mining  Engineer.  Illustrated  by  24  ?ar^ 
and  elaborate  Plates,  after  Actual  Workings  and  Apparatus.  $5.00 


28         HENRY  CAREY  BAIRD  &  CO.'S  CATALOCUE. 

WARE.—  The  Sugar  Beet. 

Including  a  History  of  the  Beet  Sugar  Industry  in  Europe,  Varietier 
of  the  Sugar  Beet,  Examination,  Soils,  Tillage,  Seeds  and  Sowing, 
Yield  and  Cost  of  Cultivation,  Harvesting,  Transportation,  Conserva- 
tion, Feeding  Qualities  of  the  Beet  and  of  the  Pulp,  etc.  By  LEWI$ 
S.  WARE,  C.  E.,  M.  E.  Illustrated  by  ninety  engravings.  8vo. 


WARN.—  The  Sheet-Metal  Worker's  Instructor: 
For  Zinc,  Sheet-  Iron,  Copper,  and  Tin-  Plate  Workers,  etc.  Contain- 
ing a  selection  of  Geometrical  Problems  ;  also,  Practical  and  Simple 
Rules  for  Describing  the  various  Patterns  required  in  the  different 
branches  of  the  above  Trades.  By  REUBEN  H.  WARN,  Practical 
Tin-  Plate  Worker.  To  which  is  added  an  Appendix,  containing 
Instructions  for  Boiler-Making,  Mensuration  of  Surfaces  and  Solids, 
Rules  for  Calculating  the  Weights  of  different  Figures  of  Iron  and 
Steel,  Tables  of  the  Weights  of  Iron,  Steel,  etc.  Illustrated  by  thirty- 
two  Plates  and  thirty-seven  Wood  Engravings.  8vo.  .  $3-00 

WARNER.  —  New  Theorems,  Tables,  and  Diagrams,  for  thft 
Computation  of  Earth-work  : 

Designed  for  the  use  of  Engineers  in  Preliminary  and  Final  Estimates 
of  Students  in  Engineering,  and  of  Contractors  and  other  non-profes- 
sional Computers.  In  two  parts,  with  an  Appendix.  Part  I.  A  Prac- 
tical Treatise;  Part  II.  A  Theoretical  Treatise,  and  the  Appendix. 
Containing  Notes  to  the  Rules  and  Examples  of  Part  I.;  Explana 
tions  of  the.  Construction  of  Scales,  Tables,  and  Diagrams,  and  i 
Treatise  upon  Equivalent  Square  Bases  and  Equivalent  Level  Heights 
By  JOHN  WARNER,  A.  M.,  Mining  and  Mechanical  Engineer.  Illus- 
f  -ated  by  14  Plates.  8vo.  .....  .  $3-oo 

WILSON.  —  Carpentry  and  Joinery  : 

Bj  JOHN  WILSON,  Lecturer  on  Building  Construction,  Carpentry  and 
Joinery,  etc.,  in  the  Manchester  Technical  School.  Third  Edition, 
with  65  full-page  plates,  in  flexible  cover,  oblong.  .  .  (Scarce.) 

WATSON.—  A  Manual  of  the  Hand-Lathe  : 

Comprising  Concise  Directions  for  Working  Metals  of  all  kinds, 
Ivory,  Bone,  and  Precious  Woods  ;  Dyeing,  Coloring,  and  French 
Polishing  ;  Inlaying  by  Veneers,  and  various  methods  practised  to 
produce  Elaborate  work  with  Dispatch,  and  at  Small  Expense.  By 
EGBERT  P.  WATSON,  Author  of  "The  Modern  Practice  of  American 
Machinists  and  Engineers."  Illustrated  by  78  engravings.  $1.50 

WATSON.  —  The  Modern   Practice  of  American  Machinists 
and  Engineers  : 

Including  the  Construction,  Application,  and  Use  of  Drills,  Lathe 
Tools,  Cutters  for  Boring  Cylinders,  and  Hollow-work  generally,  with 
the  most  Economical  Speed  for  the  same  ;  the  Results  verified  1  y 
Actual  Practice  at  the  Lathe,  the  Vise,  and  on  the  floor.  Togethei 


HENRY   CAREY    BAIRD   &   CO.'S   CATALOGUE.         29 


with  Workshop  Management,  Economy  of  Manufacture,  the  Steam 
Engine,  Boilers,  Gears,  Belting,  etc.,  etc.  By  EGBERT  P.  WATSON. 
Illustra-ed  by  eighty-six  engravings.  I2mo.  .  .  .  $2.50 

WATT.— The  Art  of  Soap  Making  : 

A  Practical  Hand-Book  of  the  Manufacture  of  Hard  and  Soft  Soaps, 
Toilet  Soaps,  etc.  Fifth  Edition,  Revised,  to  which  is  added  an 
Appendix  on  Modern  Candle  Making.  By  ALEXANDER  WATT. 
111.  I2mo $3.00 

WEATHERLY. — Treatise  on  the  Art  of  Boiling  Sugar,  Crys- 
tallizing, Lozenge-making,  Comfits,  Gum  Goods, 
And  other  processes  for  Confectionery,  including  Methods  for  Manu- 
facturing every  Description  of  Raw  and  Refined  Sugar  Goods.  A 
New  and  Enlarged  Edition,  with  an  Appendix  on  Cocoa,  Chocolate, 
Chocolate  Confections,  etc.  196  pages,  1 2mo.  (1903)  .  $1.50 

"WILL.— Tables  of  Qualitative  Chemical  Analysis  : 

With  an  Introductory  Chapter  on  the  Course  of  Analysis.  By  Pro- 
fessor HEINRICH  WILL,  of  Giessen,  Germany.  Third  American, 
from  the  eleventh  German  edition.  Edited  by  CHARLES  F.  HIMES, 
Ph.  D.,  Professor  of  Natural  Science,  Dickinson  College,  Carlisle, 
Pa.  8vo $1.50 

WILLIAMS.— On  Heat  and  Steam  : 

Embracing  New  Views  of  Vaporization,  Condensation  and  Explo- 
sion. By  CHARLES  WYE  WILLIAMS,  A.  I.  C.  E.  Illustrated.  8vo. 

$2.50 

WILSON. — First  Principles  of  Political  Economy: 

With  Reference  to  Statesmanship  and  the  Progress  of  Civilization. 
By  Professor  W.  D.  WILSON,  of  the  Cornell  University.  A  new  and 
revised  edition.  I2mo $1-5° 

WILSON.— The  Practical  Tool-Maker  and  Designer: 

A  Treatise  upon  the  Designing  of  Tools  and  Fixtures  for  Machine 
Tools  and  Metal  Working  Machinery,  Comprising  Modern  Examples 
of  Machines  with  Fundamental  Designs  for  Tools  for  the  Actual  Pro- 
duction of  the  work;  Together  with  Special  Reference  to  a  Set  of 
Tools  for  Machining  the  Various  Parts  of  a  Bicycle.  Illustrated  by 
189  engravings.  1898. $2.50 

CONTENTS  :  Introductory.  Chapter  I.  Modern  Tool  Room  and  Equipment. 
II.  Files,  Their  Use  and  Abuse.  III.  Steel  and  Tempering.  IV.  Making  Jigs. 
V.  Milling  Machine  Fixtures.  VI.  Tools  and  Fixtures  for  Screw  Machines.  VII. 
Broaching.  VIII.  Punches  and  Dies  for  Cutting  and^ Drop  Press.  IX.  Tools  for 
kf-Wa 


ments.     XI.  Drop  Forging.     XII.  Solid  Dr^wn  Shells  or  Ferrules;  Cupping  or 
Cutting,  and  Drawing ;  Breaking  Down  Shells.     XIII.  Annealing,  Picklir 

ning,     XIV.  Tools  for  Draw  Bench.     XV.  Cutting  and  Assemblir 
by  Means  of  Ratchet  Dial  Plates  at  One  Operation.     XVI.  The  Header.    SAV1I. 
Tools  for  Fox  Lathe.     XVIII.  Suggestions  for  a  Set  of  Tools  for  Machining  the 


Various  Parts  of  a  Bicycle.     XIX.  The  Plater's  Dynamo.     XX.  Conclusion— 
With  a  Few  Random  Ideas.     Appendix.     Index. 

WOODS  — Compound  Locomotives  : 

By  ARTHUR  TANNATT  WOODS.    Second  edition,  revised  and  enlarged 
by  DAVID  LEONARD  BARNES,  A.  M.,  C.  E.     8vo.    330  pp.     #3.00 


jo        HENRY   CAREY    BAIRD   &    CO.'S  CATALOGUE. 


WOHLER.— A  Hand-Bookof  Mineral  Analysis: 

By  F.  WOHLER,  Professor  of  Chemistry  in  the  University  of  Gottin- 
gen.  Edited  by  HENRY  B.  NASON,  Professor  of  Chemistry  in  the 
Renssalaer  Polytechnic  Institute,  Troy,  New  York.  Illustrated. 
I2mo.  $2.50 

WORSSAM.— On  Mechanical  Saws: 

From  the  Transactions  of  the  Society  of  Engineers,  1869.  By  S.  W. 
WORSSAM,  JR.  Illustrated  by  eighteen  large  plates.  8vo.  $1>S° 


RECENT   ADDITIONS. 

BRANNT. — Varnishes,  Lacquers,  Printing  Inks  and  Sealing  - 
Waxes : 

Their  Raw  Materials  and  their  Manufacture,  to  which  is  added  the 
Art  of  Varnishing  and  Lacquering,  including  the  Preparation  of  Put- 
ties and  of  Stains  for  Wood,  Ivory,  Bone,  Horn,  and  Leather.  By 
WILLIAM  T.  BRANNT.  Illustrated  by  39  Engravings,  338  pages. 

I2tno.      .      -.  '.     ",        '.'      '  ." $3.00 

BRANNT — The  Practical  Scourer  and  Garment  Dyer: 

Comprising  Dry  or  Chemical  Cleaning ;  the  Art  of  Removing  Stains ; 
Fine  Washing;  Bleaching  and  Dyeing  of  Straw  Hnts,  Gloves,  and 
Feathers  of  all  kinds;  Dyeing  ot  Worn  Clothes  of  all  fabrics,  in- 
cluding Mixed  Goods,  by  One  Dip ;  and  the  Manufacture  of  Soaps 
and  Fluids  for  Cleansing  Purposes.  Edited  by  WILLIAM  T.  BRANNT, 
Editor  of  "  The  Techno-Chemical  Receipt  Book."  Illustrated. 
203  pages.  I2mo.  .  .  ,  .  .  ;  .  .  $2.00 

BRANNT.— Petroleum . 

its  History,  Origin,  Occurrence,  Production,  Physical  and  Chemical 
Constitution,  Technology,  Examination  and  Uses;  Together  with 
the  Occurrence  and  Uses  of  Natural  Gas.  Edited  chiefly  from  the 
German  of  Prof.  Hans  Hoefer  and  Dr.  Alexander  Veith,  by  WM. 
T.  BRANNT.  Illustrated  by  3  Plates  and  284  Engravings.  743  pp. 
8vo.  #7.50 

BRANNT. — A  Practical  Treatise  on  the  Manufacture  of  Vine- 
gar and  Acetates,  Cider,  and  Fruit- Wines  : 
Preservation  of  Fruits  and  Vegetables  by  Canning  and  Evaporation; 
Preparation  of  Fruit-Butters,  Jellies,  Marmalades,  Catchups,  Pickles, 
Mustards,  etc.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated  by  79  Engravings.  479  pp.  8vo,  $5*-°° 

BRANNT.— The  Metal  Worker's    Handy-Book   of  Receipts 

and  Processes : 

Being  a  Collection  of  Cliemical  Formulas  and  Practical  Manipula- 
tions for  the  working  of  all  Metals;  including  the  Decoration  and 
Beautifying  of  Articles  Manufactured  therefrom,  as  well  as  their 
Preservation.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated.  I2mo.  $2.50 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.         31 

DEITE.— A  Practical  Treatise  on  the   Manufacture  of  Per- 
fumery : 

Comprising  directions  for  making  all  Kinds  of  Perfumes,  Sache* 
Powders,  Fumigating  Materials,  Dentifrices,  Cosmetics,  etc.,  with  a 
full  account  of  the  V  -latile  Oils,  Balsams,  Resins,  and  other  Natural 
and  Artificial  Perfume-substances,  including  the  Manufacture  of 
Fruit  Ethers,  and  tests  of  their  purity.  By  Dr.  C.  DEITE.  assisted 
by  L.  BORCHERT,  F.  EICHBAUM,  E.  KUGLER,  H.  TOEFFNER,  and 
other  experts.  From  the  German,  by  WM.  T.  BRANNT.  28  Engrav- 
ings. 358  pages.  8vo. 13.00 

2D  WARDS. — American    Marine  Engineer,    Theoretical   and 

Practical : 

With  Examples  of  the  latest  and  most  approved  American  Practice. 
By  EMORY  EDWARDS.  85  illustrations.  i2mo.  .  .  $2.50 

EDWARDS.— 900    Examination   Questions  and   Answers: 
For  Engineers  and   Firemen   (Land  and  Marine)  who  desire  to  ob- 
tain a   United   States  Government  or  State  License.     Pocket-book 
form,  gilt  edge $1.50 

FLEMMING. — Practical  Tanning: 

A  Handbook  of  Modern  Processes,  Receipts,  and  Suggestions  for  the 
Treatment  of  Hides,  Skins,  and  Pelts  of  Every  Description.  By 
Lewis  A.  Fleinming.  American  Tanner.  472pp.  8 vo.  (1903)  $4.00. 

POSSELT.— The  Jacquard  Machine  Analysed  and  Explained: 
With  an  Appendix  on  the  Preparation  of  Jacquard  Cards,  and 
Practical  Hints  to  Learners  of  Jacquard  Designing.  By  E.  A. 
POSSELT.  With  230  illustrations  and  numerous  diagrams.  127  pp. 
4to #3.00 

POSSELT.— Recent   Improvements    in    Textile    Machinery, 
Part  III: 

Processes  Required  for  Converting  Wool,  Cotton,  Silk,  from  Fibre 
to  Finished  Fabric,  Covering  both  Woven  and  Knit  Goods  ;  Con- 
struction of  the  most  Modern  Improvements  in  Preparatory  Machin- 
ery, Carding,  Combing,  Drawing,  and  Spinning  Machinery,  Winding, 
Warping,  Slashing  Machinery  Looms,  Machinery  for  Knit  Goods, 
Dye  Stuffs,  Chemicals,  Soaps,  Latest  Improved  Accessories  Relat- 
ing to  Construction  and  Equipment  of  Modern  Textile  Manufactur- 
ing Plants.  By  E.  A.  POSSKLT.  Completel-  Illustrated.  410. 

#7-50 
RICH.— Artistic  Horse.Shoeing: 

A  Practical  and  Scientific  Treatise,  giving  Improved  Methods  of 
Shoeing,  with  Special  Directions  for  Shaping  Shoes  to  Cure  Different 
Diseases  of  the  Foot,  and  for  the  Correction  of  Faulty  Action  in 
Trotters.  By  GEORGE  E.  RICH.  62  Illustrations.  153  pa^es 
•emu  ....  $1.00 


32       HENRY   CAREY   BAIRD  &  CO.'S  CATALOGUE. 

RICH ARDSON.— Practical  Blacksmithing : 
A  Collection  of  Articles  Contributed  at  Different  Times  by  Skilled 
Workmen  to  the  columns  of  "  The  Blacksmith  and  Wheelwright," 
and  Covering  nearly  the  Whole  Range  of  Blacksmithing,  from  the 
Simplest  Job  of  Work  to  some  of  the  Most  Complex  Forgings. 
Compiled  and  Edited  by  M.  T.  RICHARDSON. 

Vol.1.  210  Illustrations.  224  pages.  I2mo.  .  .  $1.00 
Vol.  II.  230  Illustrations.  262  pages.  I2mo.  .  .  $1.00 
Vol.  III.  390  Illustrations.  307  pages.  I2mo.  .  .  $1.00 

t     Vol.  IV.     226  Illustrations.     276  pages.     I2mo.      ,         .         $1.00 

RICHARDSON,— The  Practical  Horseshoer: 
Being  a  Collection  of  Articles  on  Horseshoeing  in  all  its  Branched 
which  have  appeared  from  time  to  time  in  the  columns  of  "  1  he* 
Blacksmith  and  Wheelwright,"  etc.     Compiled  and  edited  by  M.  T.' 
RICHARDSON.     174  illustrations #1.00 

ROPER. — Instructions    and    Suggestions    for   Engineers   and 

Firemen : 
By  STEPHEN  ROPER,  Engineer.     i8mo.     Morocco        .        #2.00 

ROPER. — The  Steam  Boiler:  Its  Care  and  Management: 
By  STEPHEN  ROPER,  Engineer.     I2mo.,  tuck,  gilt  edges.         $2.00 

ROPER. — The  Young  Engineer's  Own  Book: 

Containing  an  Explanation  of  the  Principle  and  Theories  on  which 
the  Steam  Engine  as  a  Prime  Mover  is  Based.  By  STEPHEN  ROPER. 
Engineer.  160  illustrations,  363  pages.  i8mo.,  tuck  .  $2.50 

ROSE. — Modern  Steam- Engines: 

An  Elementary  Treatise  upon  the  Steam-Engine,  written  in  Plain 
language ;  for  Use  in  the  Workshop  as  well  as  in  the  Drawing  Office. 
Giving  Full  Explanations  of  the  Construction  of  Modern  Steanv 
Engines :  Including  Diagrams  showing  their  Actual  operation.  To- 
gether with  Complete  but  Simple  Explanations  of  the  operations  of 
Various  Kinds  of  Valves,  Valve  Motions,  and  Link  Motions,  etc., 
thereby  Enabling  the  Ordinary  Engineer  to  clearly  Understand  the 
Principles  Involved  in  their  Construction  and  Use,  and  to  Plot  out 
their  Movements  upon  the  Drawing  Board.  By  JOSHUA  ROSE.  M.  E. 
Illustrated  by  422  engravings.  Revised.  358  pp.  .  .  $6.00 

ROSE. — Steam  Boilers: 

A  Practical  Treatise  on  Boiler  Construction  and  Examination,  for  the 
Use  of  Practical  Boiler  Makers,  Boiler  Users,  and  Inspectors;  and 
embracing  in  plain  figures  all  the  calculations  necessary  in  Designing 
or  Classifying  Steam  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  73  engravings.  250  pages.  8vo $2.50 

SCHRIBER.— The  Complete  Carriage  and  Wagon  Painter: 
A  Concise  Compendium  of  the  Art  of  Painting  Carriages,  Wagons, 
and  Sleighs,  embracing  Full  Directions  in  all  the  Various  Branches, 
including  Lettering,  Scrolling,  Ornamenting,  Striping,  Varnishing, 
and  Coloring,  with  numerous  Recipes  for  Mixing  Colors.  73  Illus- 
trations. 177  pp.  I2mo 


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